554 lines
24 KiB
Plaintext
554 lines
24 KiB
Plaintext
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<h2>General Navigation</h2>
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<h3>Model View</h3>
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To pan the view, center-drag with the mouse. (The center button
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is typically actuated by pressing on the scroll wheel.)
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To rotate the view, right-drag with the mouse. This will rotate
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the part about a horizontal or vertical axis. To rotate the part
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within the plane of the screen, Ctrl+right-drag with the mouse.
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To zoom in or out, rotate the scroll wheel. It is also possible
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to zoom in or out by using the View menu, or the associated
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keyboard shortcuts (+ and -).
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It is also possible to pan by Shift+right-dragging, or to rotate
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by Shift+center-dragging. This makes MechSketch usable on certain
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laptop keyboards that don't provide a center mouse button.
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If a workplane is active, then choose Sketch -> In Workplane (or
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press W) to align the view to the workplane. After doing this,
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the plane of the screen is coincident with the workplane.
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<h3>Dimension Entry and Units</h3>
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Dimensions may be displayed in either millimeters or inches.
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Millimeter dimensions are always displayed with two digits
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after the decimal point (45.23), and inch dimensions are always
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displayed with three (1.781).
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Choose View -> Dimensions in ... to change the current display
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units. This does not change the model; if the user changes from
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inches to millimeters, then a dimension that was entered as 1.0
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is now displayed as 25.40.
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All dimensions are entered in the current display units. In most
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places where a dimension is expected, it's possible to enter an
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arithmetic expression ("4*20 + 7") instead of a single number.
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<h3>Show / Hide Entities</h3>
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As the sketch becomes more complex, it may be useful to hide
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unnecessary information. MechSketch provides several different
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controls for this.
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In the second and third line of the text window, links are
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provided to hide and show different types of entity. These are:
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wrkpls -- When a new "Sketch In New Workplane" group is
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created, an associated workplane is created
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automatically. If wrkpls is hidden, then that
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workplane is visible only when its associated
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group is active. If wrkpls is shown, then the
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workplane is always visible.
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normals -- By default, normals are drawn as blue-grey arrows,
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in the direction of the normal. These normals may
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be hovered and selected with the mouse, for
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example in order to constrain them. This link
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may be used to hide them.
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points -- By default, points are drawn as green squares.
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These points may be hovered and selected with the
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mouse, for example in order to constrain them.
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This link may be used to hide them. If points are
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hidden, then they will still appear when the mouse
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hovers over them, and may still be selected.
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constraints - When a constraint is created, a graphical
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representation of that constraint is displayed
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in purple. The constraints in a group are
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visible only when that group is active. To hide
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them even then, use this link.
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shaded -- The 3d part is displayed as an opaque solid,
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with lighting effects to give the impression of
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depth. This link may be used to disable that
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view.
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faces -- Some surfaces on the 3d model may be selected.
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For example, the user can select a plane face
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of the part, and constrain a point to lie on
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that plane. If faces are shown, then the faces
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will appear highlighted when the mouse hovers
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over them. The user can click the mouse to
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select the face, as they would for any other
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entity.
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As a convenience, faces are automatically
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hidden when a new sketch group is created,
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and automatically shown when a new extrusion is
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created. If this behavior is not what's desired,
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then the faces can be shown or hidden manually
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with this link.
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mesh -- The 3d model of the part consists of many
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triangles; for example, a flat polygon with
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n sides is broken down into n - 2 triangles.
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Use this link to show the triangles on the
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model. In general, this is useful only for
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debugging, or to see how fine the mesh is
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before exporting it.
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hidden-lines - With the part in a given orientation, some of
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the lines in the part will be invisible,
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because an opaque solid is between the line and
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the "camera". To show those lines anyways, as
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if the part were transparent, use this link.
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This may be useful when creating a sketch that
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lies within the volume of the part.
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In addition to the above options, it is possible to hide and show
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entire groups. If a group is hidden, then all of the entities
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(line segments, circles, arcs, points, etc.) from that group
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are hidden.
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To hide a group, go to the home screen in the text window, by
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pressing Esc or choosing the link at the top left. A list of
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groups is displayed, along with their visibility. If a group is
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visible, then the "show" column contains the word "yes" in green.
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Click the "yes"; it now appears as a greyed "no", and the group
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is hidden.
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The show / hide status of groups is saved in the part file. If
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a part is imported into an assembly, then entities that were
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visible in the part file will be visible in the assembly, and
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entities that were hidden will be hidden.
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<h3>Active Workplane</h3>
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MechSketch represents all geometry in 3d; it's possible to draw
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line segments anywhere, not just in some plane.
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This freedom is not always useful, so MechSketch also makes it
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possible to draw in a plane. If a workplane is active, then all
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entities that are drawn will be constrained to lie that plane.
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When MechSketch starts with a new empty file, a workplane parallel
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to the XY plane is active.
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<h3>Active Group</h3>
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Any groups that go after the active group will be hidden
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<h2>Sketch Entities</h2>
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<h3>Datum Point</h3>
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<h3>Workplane</h3>
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<h3>Line Segment</h3>
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<h3>Rectangle</h3>
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A rectangle consists of two vertical line segments, and two
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horizontal line segments, arranged to form a closed curve.
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Initially, the rectangle is specified with the mouse by two
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diagonally opposite corners. The line segments (and points)
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in the rectangle may be constrained in the same way as ordinary
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line segments.
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It would be possible to draw the same figure by hand, by drawing
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four line segments and inserting the appropriate constraints. The
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rectangle command is a faster way to draw the exact same thing.
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A workplane must be active when the rectangle is drawn, since
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the workplane defines the meaning of "horizontal" and "vertical".
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<h3>Circle</h3>
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<h3>Arc of a Circle</h3>
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Tangent arcs may be created automatically. To do so, first select
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a point where two line segments join. Then choose Sketch ->
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Arc of a Circle; the arc will be created, and automatically
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constrained tangent to the two line segments.
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The initial line segments will become construction lines, and
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two new lines will be created, that join up to the arc.
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The arc's diameter may then be constrained in the usual way, with
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Distance / Diameter or Equal Length / Radius constraints. This
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is a simple way to round a sharp corner.
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<h3>Bezier Cubic Segment</h3>
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<h3>Text in a TrueType Font</h3>
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<h2>Constraints</h2>
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<h3>General</h3>
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<h3>Reference Dimensions</h3>
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By default, the dimension drives the geometry. If a line segment
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is constrained to have a length of 20.00 mm, then the line
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segment is modified until that length is accurate.
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A reference dimension is the reverse: the geometry drives the
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dimension. If a line segment has a reference dimension on its
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length, then it's still possibly to freely change that length,
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and the dimension displays whatever that length happens to be. A
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reference dimension does not constrain the geometry.
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To change a dimension into a reference dimension, choose
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Constrain -> Toggle Reference Dimension. A reference dimension
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is drawn with "REF" appended to the displayed length or angle.
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Double-clicking a reference dimension does nothing; the dimension
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is specified by the geometry, not the user.
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<h3>Angle</h3>
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When two lines intersect, four angles are formed. The
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opposite angles are equal; to change which opposite angle is
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displayed, drag the label, and the arc will follow. If the wrong
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supplementary angle is displayed, then select the constraint
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and choose Constrain -> Other Supplementary Angle.
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<h3>Comment</h3>
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A comment is a single line of text that appears on the drawing.
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When the comment is created, it appears in the center of the
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screen. To move the comment, drag it with the mouse. To change
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the text, double-click it.
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The comment has no effect on the geometry; it is only a
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human-readable note.
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<h2>Groups</h2>
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<h3>General</h3>
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All groups have a name. When the group is created, a default name
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(e.g., "g008-extrude") is assigned. The user may change this name;
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to do so, go to the group's page in the text window, and choose
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[rename].
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Groups that create a solid (e.g. extrudes or sweeps) have a "MERGE
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AS" option, which is displayed in the page in the text window.
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The group can be merged as union, which adds material to the
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model, or as difference, which cuts material away.
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The group's page in the text window also includes a list of all
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requests, and of all constraints. To identify a constraint or a
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request, hover the mouse over its name; it will appear highlighted
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in the graphics window. To select it, click on the link in the
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text window. This is equivalent to hovering over and clicking
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the actual object in the graphics window.
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<h3>Sketch in 3d</h3>
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<h3>Sketch in New Workplane</h3>
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A point and two line segments
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The new workplane has its origin at the specified point. The
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workplane is parallel to the two lines. If the point and
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two are two edges on a plane face of the part, and a vertex
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on that plane face, then the resulting workplane will be
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coincident with that face (i.e., the user will be drawing
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on that face).
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A point
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The new workplane has its origin at the specified point. The
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workplane is orthogonal to the base coordinate system; for
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example, its horizontal and vertical axes might lie in the
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+y and -z directions, or +x and -z, or any other combination.
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The orientation of the workplane is inferred from the
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position of the view when the workplane is created; the
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view is snapped to the nearest orthographic view, and the
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workplane is aligned to that.
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If a part consists mostly of ninety degree angles, then this
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is a quick way to create workplanes.
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<h3>Step Translating</h3>
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<h3>Step Rotating</h3>
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<h3>Extrude</h3>
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If a workplane is active when the group is created, then the
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extrude path is automatically constrained to be normal to that
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workplane. This means, for example, that a rectangle is extruded
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to form a rectangular prism. The extrusion has one degree of
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freedom, so a single distance constraint will fully constrain it.
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This is usually the desired behaviour.
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If no workplane is active when the group is created, then the
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extrude path may be in any direction. This means that a rectangle
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could be extruded to form a parallelepiped. The extrusion has
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three degrees of freedom. This is not typically useful.
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<h3>Lathe</h3>
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<h3>Sweep</h3>
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<h3>Helical Sweep</h3>
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<h3>Import / Assemble</h3>
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In MechSketch, there is no distinction between "part" files and
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"assembly" files; it's always possible to import one file into
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another. An "assembly" is just a part file that imports one or
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more other parts.
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The imported file is not editable within the assembly. It is
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imported exactly as it appears in the source file, but with an
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arbitrary position and orientation. This means that the imported
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part has six degrees of freedom.
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To move (translate) the part, click any point on the imported
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part and drag it. To rotate the part, click any point and Shift+
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or Ctrl+drag it. The position and orientation of the part may be
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fixed with constraints, in the same way that any other geometry
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is constrained.
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The Same Orientation constraint is particularly useful when
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importing parts. This one constraint completely determines the
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imported part's rotation. (Select a normal on the imported part,
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select some other normal to constrain it against, and choose
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Constrain -> Same Orientation).
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Import groups have a special "MERGE AS" option: in addition
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to the usual "union" and "difference", they have "assemble".
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The "assemble" option is identical to "union", except that
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it displays a warning if the components intersect with each
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other. This is useful when checking to see if the assembled parts
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interfere. If the parts interfere, then a warning is displayed
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underneath the "MERGE AS" line in the group's text window page.
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The interfering surfaces are also highlighted in the graphics
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window, in red with black stripes.
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When an assembly file is loaded, MechSketch loads all of the
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imported files as well. If the imported files are not available,
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then an error occurs. When transfering an assembly file to another
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computer, it's necessary to transfer all of the imported files
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as well.
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<h2>Export</h2>
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<h3>Bitmap Image</h3>
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This option will export a bitmap image of whatever is displayed
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on-screen. It is equivalent to taking a screenshot. This option
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is useful for producing human-readable drawings.
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Choose File -> Export Image. The file is exported as a PNG,
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which most graphics software can open.
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<h3>2d Vector (DXF)</h3>
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This option will generate a 2d vector file that represents a
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specified plane in the part. Most 2d CAM software, including the
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software that ships with laser or waterjet cutters, will accept
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a DXF file.
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Before exporting a DXF, it is necessary to specify which plane of
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the part should be exported. This may be specified by:
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a face:
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Any surfaces coplanar with that plane face will appear in the
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file. The faces must be shown before they can be selected;
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click the link in the third line of the text window.
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a point, and two lines or vectors:
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The export plane is through the point, and parallel to
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the two lines or vectors. If the two lines or vectors are
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perpendicular, then they will become the x and y axis in the
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DXF file. Whichever line is more horizontal in the current
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view becomes the x axis, and the other one becomes the y.
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This means that it's possible to rotate the exported DXF
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through ninety degrees by rotating the view through ninety
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degrees (in the plane of that face). Similarly, by rotating
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the part around to look at the face from behind instead of
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in front, the exported DXF is mirrored.
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the active workplane
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If a workplane is active, and nothing is selected when the
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export command is chosen, then MechSketch will export any
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surfaces that are coplanar with the active workplane. The
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workplane's horizontal and vertical axes become the x and
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y axis in the DXF file.
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The units of the DXF file are determined by the export scale
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factor, which may be specified in the configuration screen.
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<h3>3d Mesh (STL)</h3>
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This option will generate a 3d triangle mesh that represents
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the entire part. Most 3d CAM software, including the software
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for most 3d printers, will accept an STL file.
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The mesh from the active group will be exported; this is the
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same mesh that is displayed on screen. The coordinate system
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for the STL file is the same coordinate system in which the part
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is drawn. To use a different coordinate system (e.g., to rotate
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or translate the part), create an assembly with the part in the
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desired position, and then export an STL file of the assembly.
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The units of the STL file are determined by the export scale
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factor, which may be specified in the configuration screen.
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<h2>Configuration</h2>
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<h3>Material Colors</h3>
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In the text window screen for certain groups (extrude, lathe,
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sweep), a palette of eight colors is displayed. This palette
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allows the user to choose the color of any surfaces generated
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by that group.
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These eight colors are specified here, by their components.
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The components go from 0 to 1.0. The color "0, 0, 0" is black,
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and "1, 1, 1" is white. The components are specified in the order
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"red, green, blue".
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A change to the palette colors does not change the color of any
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existing surfaces in the sketch, even if the color of an existing
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surface no longer appears in the palette.
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<h3>Light Directions</h3>
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The 3d part is displayed with simulated lighting, to produce
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the impression of depth. The directions and intensities of these
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lights may be modified according to user preference.
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The lights do not have a position; they have only a direction,
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as if they were coming from very far away. This direction is
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specified in 3 components, "right, top, front". The light with
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direction "1, 0, 0" is coming from the right of the screen.
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The light with direction "-1, 0, 0" is coming from the left of
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the screen. The light with direction "0, 0, 1" is coming from
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in front of the screen.
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The intensity must lie between 0 and 1. A light with intensity
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0 has no effect, and 1 is full brightness.
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Two lights are available. If only one is desired, then the second
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may be disabled by setting its intensity to zero. When the part
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is rotated or translated, the lights do not move.
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<h3>Chord Tolerance</h3>
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MechSketch does not represent curved edges or surfaces exactly.
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Any curves are broken down into piecewise linear segments,
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and surfaces are represented as triangles.
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This introduces some error. The chord tolerance determines how
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much error is introduced; it is the maximum distance between
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the exact curve and the line segments that approximate it. If
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the chord tolerance is decreased, then more line segments will
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be generated, to produce a better approximation.
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The chord tolerance is specified in units of screen pixels. This
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means that when the user zooms in on the model, a better
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approximation is produced.
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The same tolerance is used for the mesh that's displayed on
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screen, and for the mesh that is used to export to a file. It
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may be helpful to use a large chord tolerance (2-5 pixels) while
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drawing, for fast response, and then temporarily specify a small
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chord tolerance (~0.5 pixels) before exporting an STL or DXF file.
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<h3>Perspective Factor</h3>
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To display a 3d part on-screen, it must be projected into 2d. One
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common choice is a parallel projection. In a parallel projection,
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any two lines that are parallel in real life are also parallel
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in the drawing. A parallel projection is also known as an
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axonometric projection. Isometric and orthographic views are
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examples of parallel projections.
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Another way to transform the image into 2d is with a perspective
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projection. In a perspective projection, objects closer to the
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"camera" appear larger than objects that are farther away. This
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means that some lines that are parallel in real life will not be
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parallel in the drawing; they will converge at a vanishing point.
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A perspective projection will often look more realistic, and
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gives a better impression of depth. The disadvantage is that
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the perspective distorts the image, and may cause confusion.
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By default, MechSketch displays a parallel projection. To display
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a perspective projection, set the perspective factor to something
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other than zero. The distance from the "camera" to the model is
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equal to one thousand pixels divided by the perspective factor.
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<h3>Edge Color</h3>
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The surfaces of the 3d part are shaded according to the specified
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lighting. Different faces will catch the light at slightly
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different angles, and will therefore appear slightly brighter
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or darker. This permits the viewer to distinguish the boundary
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between the faces.
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Depending on the lighting, this may not provided very much
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constrast. To make the edges of the part more visible, it's
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possible to emphasize them with a solid-color line.
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If the edge color is specified as "0,0,0", then no emphasized
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edges will be drawn. If any other color is specified, then the
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edges will be drawn in that color. The edge color is specified
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in the same format as for the material color.
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<h3>Export Scale Factor</h3>
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Internally, MechSketch represents lengths in millimeters. Before
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exporting geometry to an STL or DXF file, these lengths are
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divided by the export scale factor. This scale factor determines
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the units for the exported file.
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If the scale factor is set equal to 1, then exported files are
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|
in millimeter units. If the scale factor is set equal to 25.4,
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then the exported files are in inch units, since 1 inch = 25.4 mm.
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MechSketch works in a right-handed coordinate system. If the
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scale factor is negative, then the exported file will appear in
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a left-handed coordinate system (so that a right-handed screw
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thread will become left-handed).
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<h2>Licensing</h2>
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As downloaded, MechSketch does not include a license file. This means
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|
that it cannot create files with more than seven groups. Larger files
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|
may be opened, but not modified. This light version of MechSketch
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|
is intended for evaluation, but non-commercial / personal use is
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|
also permitted.
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The licensed version of MechSketch can create files with an unlimited
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|
number of groups.
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When a license is purchased, a license file ("mechsketch.license")
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will be sent via email. To activate the license, save this file
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|
somewhere on your computer. In MechSketch, choose Help -> Load
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License... A file dialog box will appear; select the license file.
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No license server or dongle is required, and licenses do not expire.
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