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Swap meaning of middle and right mouse buttons (now center means 

drag, right means pan), and extend reference manual.

[git-p4: depot-paths = "//depot/solvespace/": change = 1845]
solver
Jonathan Westhues 2008-07-18 05:31:22 -08:00
parent a783f14eff
commit d2c4d2cdb7
2 changed files with 502 additions and 46 deletions
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doc/reference.txt
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@ -1,27 +1,49 @@
This is a reference manual for MechSketch. This document is not intended
for new users; to learn about this program, see the video tutorials.
<h2>General Navigation</h2> <h2>General Navigation</h2>
<h3>Model View</h3> Two windows appear on the screen: a larger window that contains
graphics, and a smaller window that contains text. The graphics
window is used to draw the geometry, and to view the 3d model. The
text window provides information about the model, and may also be
used to modify settings and numerical parameters.
To pan the view, center-drag with the mouse. (The center button <h3>Graphics Window and Model View</h3>
is typically actuated by pressing on the scroll wheel.)
To rotate the view, right-drag with the mouse. This will rotate To pan the view, right-drag with the mouse.
the part about a horizontal or vertical axis. To rotate the part
within the plane of the screen, Ctrl+right-drag with the mouse.
To zoom in or out, rotate the scroll wheel. It is also possible To rotate the view, center-drag with the mouse. This turns the
to zoom in or out by using the View menu, or the associated part over, so that the surfaces that used to be hidden (because
keyboard shortcuts (+ and -). they were facing backwards, away from the viewer) become visible.
It is also possible to pan by Shift+right-dragging, or to rotate To rotate the view within the plane of the monitor,
by Shift+center-dragging. This makes MechSketch usable on certain Ctrl+center-drag with the mouse.
laptop keyboards that don't provide a center mouse button.
It is also possible to pan by Shift+center-dragging, or to rotate
by Shift+right-dragging.
To zoom in or out, rotate the scroll wheel. It is also possible to
zoom by using the View menu, or the associated keyboard shortcuts
(+ and -).
To zoom to the extent of the part, choose View -> Zoom To
Fit. This adjusts the zoom level so that the part fits exactly
on the screen, and then pans to center the part. The rotation
of the part is not affected.
If a workplane is active, then choose Sketch -> In Workplane (or If a workplane is active, then choose Sketch -> In Workplane (or
press W) to align the view to the workplane. After doing this, press W) to align the view to the workplane. After doing this,
the plane of the screen is coincident with the workplane. the plane of the screen is coincident with the workplane.
The x, y, and z coordinate axes are always drawn at the bottom
left of the graphics window, in red, green, and blue. These axes
are live. They can be highlighted and selected with the mouse, in
the same way as any other normals. (This means that the coordinate
axes are always conveniently available on-screen, which is useful
e.g. when constraining a line parallel to the x-axis.)
<h3>Dimension Entry and Units</h3> <h3>Dimension Entry and Units</h3>
Dimensions may be displayed in either millimeters or inches. Dimensions may be displayed in either millimeters or inches.
@ -38,14 +60,41 @@
places where a dimension is expected, it's possible to enter an places where a dimension is expected, it's possible to enter an
arithmetic expression ("4*20 + 7") instead of a single number. arithmetic expression ("4*20 + 7") instead of a single number.
<h3>Text Window</h3>
The text window appears as a floating palette window. It may
be shown or hidden by pressing Tab, or by choosing View ->
Show Text Window.
The text window works like a web browser. Any underlined text
is a link. To activate a link, click it with the mouse. The links
may be used to navigate to other pages in the text window. For
example, the "home" screen is a list of groups in the sketch:
<img src="/pics/ref-text-window.png" />
To navigate to a group's page, click on that group's name (e.g.,
"g002-sketch-in-plane". The links may also taken actions in the
sketch. For example, in the above screenshot, all of the groups
are shown. To hide a group, click on the word "yes" in the
"show" column.
As a convenience, the text window will sometimes automatically
navigate to a page that is likely to be relevant. For example,
when a new group is created, the text window displays that new
group's page. It's always possible to navigate to a different
page, by clicking the "home" link at the top left corner (or
pressing Esc), and following the links from there.
<h3>Show / Hide Entities</h3> <h3>Show / Hide Entities</h3>
As the sketch becomes more complex, it may be useful to hide As the sketch becomes more complex, it may be useful to hide
unnecessary information. MechSketch provides several different unnecessary information. MechSketch provides several different
controls for this. ways to do this.
In the second and third line of the text window, links are In the second and third line of the text window, links are
provided to hide and show different types of entity. These are: provided to hide and show different things. These are:
wrkpls -- When a new "Sketch In New Workplane" group is wrkpls -- When a new "Sketch In New Workplane" group is
created, an associated workplane is created created, an associated workplane is created
@ -75,7 +124,7 @@
shaded -- The 3d part is displayed as an opaque solid, shaded -- The 3d part is displayed as an opaque solid,
with lighting effects to give the impression of with lighting effects to give the impression of
depth. This link may be used to disable that depth. This link may be used to hide that
view. view.
faces -- Some surfaces on the 3d model may be selected. faces -- Some surfaces on the 3d model may be selected.
@ -104,11 +153,11 @@
hidden-lines - With the part in a given orientation, some of hidden-lines - With the part in a given orientation, some of
the lines in the part will be invisible, the lines in the part will be invisible,
because an opaque solid is between the line and because they are buried inside the solid part.
the "camera". To show those lines anyways, as To show those lines anyways, as if the part
if the part were transparent, use this link. were transparent, use this link. This may be
This may be useful when creating a sketch that useful when drawing a sketch that lies within
lies within the volume of the part. the volume of the part.
In addition to the above options, it is possible to hide and show In addition to the above options, it is possible to hide and show
entire groups. If a group is hidden, then all of the entities entire groups. If a group is hidden, then all of the entities
@ -132,27 +181,113 @@
MechSketch represents all geometry in 3d; it's possible to draw MechSketch represents all geometry in 3d; it's possible to draw
line segments anywhere, not just in some plane. line segments anywhere, not just in some plane.
This freedom is not always useful, so MechSketch also makes it This freedom is not always useful, so MechSketch also makes
possible to draw in a plane. If a workplane is active, then all it possible to draw in a plane. If a workplane is active, then
entities that are drawn will be constrained to lie that plane. all entities that are drawn will be forced to lie that plane.
The active workplane ("wrkpl") is indicated in the top line of
the text window, at the right.
When MechSketch starts with a new empty file, a workplane parallel When MechSketch starts with a new empty file, a workplane parallel
to the XY plane is active. to the XY plane is active. To deactivate the workplane, and draw
in 3d, choose Sketch -> Anywhere In 3d.
To activate a workplane, select it, and then choose Sketch ->
In Workplane. When a workplane is activated, the view is aligned
onto that workplane. (The workplane remains active until the
user chooses Sketch -> Anywhere In 3d, or a different workplane
is activated. If the user rotates the view, so that the view
is no longer aligned onto the workplane, then the workplane
remains active.)
In a "Sketch in New Workplane" group, the group's associated
workplane may be activated by choosing Sketch -> In Workplane;
there is no need to select it first.
<h3>Active Group</h3> <h3>Active Group</h3>
Any groups that go after the active group will be hidden When a new line, circle, or other curve is created, it will be
created in the active group.
Geometry from the active group is drawn in white; geometry from
earlier groups is drawn in brown. Later groups are hidden.
In the text window's home screen (press Escape, or choose the
link in the top left corner), the active group's line in the
list of groups has "yes" in the "actv" column. All other groups
(except g001-#references, which cannot be activated) have "no"
in that column. To activate an inactive group, click on the "no".
<h2>Sketch Entities</h2> <h2>Sketch Entities</h2>
<h3>Construction Geometry</h3>
In normal operation, the user draws line and curves in a
sketch. Those curves describe the geometry to be manufactured;
ultimately, the endmill or the laser or some other tool will
cut along those curves.
In some cases, it is useful to draw a line that should not appear
on the final part. For example, the user may wish to draw a center
line for a symmetric part; but that center line only exists as
a guide, and should not actually get exported with the CAM data.
Or the user may wish to draw the axis of revolution for a lathe
group. These lines are called construction lines.
To mark an entity as construction-only, choose Sketch -> Toggle
Construction. A construction entity will behave just like any
other entity, except that it is drawn in green, and does not
contribute to the geometry for export (or for extrusion or
lathing or sweeping).
<h3>Datum Point</h3> <h3>Datum Point</h3>
This entity is defined by a single point.
If a workplane is active when the datum point is created,
then that datum point will always lie in the workplane. If no
workplane is active, then the datum point will be free in 3d.
(This is the same behaviour as for all points, including e.g. the
endpoints of a line segment.)
Datum points are typically used as construction geometry. The user
might place datum points in order to simplify the dimensioning
of line segments or other entities.
<h3>Workplane</h3> <h3>Workplane</h3>
This entity is specified by a point and a normal. The point
defines its origin, and the normal defines its orientation.
A workplane makes it possible to draw a section in 2d. If a
workplane is active, then any entities that are drawn must lie
in that workplane.
It's almost never necessary to create workplanes explicitly.
Instead, create a new Sketch in New Workplane group.
<h3>Line Segment</h3> <h3>Line Segment</h3>
This entity is specified by its two endpoints. If a workplane is
active, then the two endpoints will always lie in that workplane.
To create the line segment, choose Sketch -> Line Segment, and
then left-click one endpoint of the line. Then release the mouse
button; the other endpoint is now being dragged.
To create another line segment, that shares an endpoint with
the line segment that was just created, left-click again. This
is a fast way to draw closed polygons.
To stop drawing line segments, press Escape, or right- or
center-click the mouse. MechSketch will also stop drawing new
line segments if an automatic constraint is inserted. (For
example, draw a closed polygon by left-clicking continuously, and
then hovering over the starting point before left-clicking the
last time. The endpoint of the polyline will be constrained to
lie on the starting point, and since a constraint was inserted,
MechSketch will stop drawing.)
<h3>Rectangle</h3> <h3>Rectangle</h3>
A rectangle consists of two vertical line segments, and two A rectangle consists of two vertical line segments, and two
@ -171,8 +306,40 @@
<h3>Circle</h3> <h3>Circle</h3>
This entity is specified by its center point, by its diameter,
and by its normal.
To create the circle, choose Sketch -> Circle, and then left-click
the center. Then release the mouse button; the diameter of
the circle is now being dragged. Left-click again to place
the diameter.
If a workplane is active, then the center point must lie in
that workplane, and the circle's normal is parallel to the
workplane's normal (which means that the circle lies in the
plane of the workplane).
If no workplane is active, then the center point is free in space,
and the normal may be dragged (or constrained) to determine the
circle's orientation.
<h3>Arc of a Circle</h3> <h3>Arc of a Circle</h3>
This entity is specified by its center point, the two endpoints,
and its normal.
To create the arc, choose Sketch -> Arc of a Circle, and then
left-click one of its endpoints. Then release the mouse button;
the other endpoint is now being dragged. The center is also being
dragged, in such a way as to form an exact semi-circle.
Left-click again to place the other endpoint, and then drag the
center to the desired position. The arc is drawn counter-clockwise
from the first point to the second.
The arc must be drawn in a workplane; it cannot be drawn in
free space.
Tangent arcs may be created automatically. To do so, first select Tangent arcs may be created automatically. To do so, first select
a point where two line segments join. Then choose Sketch -> a point where two line segments join. Then choose Sketch ->
Arc of a Circle; the arc will be created, and automatically Arc of a Circle; the arc will be created, and automatically
@ -187,13 +354,61 @@
<h3>Bezier Cubic Segment</h3> <h3>Bezier Cubic Segment</h3>
This entity is specified by its four Bezier points: two endpoints,
and two (in general, off-curve) control points.
To create the Bezier cubic, choose Sketch -> Bezier Cubic
Segment. Then left-click one endpoint of the cubic segment.
Release the mouse button; the other endpoint of the cubic segment
is now being dragged.
The two control points are intially placed on the straight line
between the endpoints; this means that the cubic originally
appears as a straight line. Drag the control points to produce
the desired curve.
<h3>Text in a TrueType Font</h3> <h3>Text in a TrueType Font</h3>
This entity is defined by two points, at the top left and bottom
left of the text. The distance between the points determines the
height of the text; the angle of the line between them determines
the orientation of the text, and their position determines the
text's position.
To create the text, choose Sketch -> Text in TrueType Font. Then
left-click the top left point of the text. The bottom right point
of the text is now being dragged; left-click again to place it.
To change the font, select the text entity. A list of installed
fonts appears in the text window; click the font name to select
it. To change the displayed text, select the text entity and
click the [change] link in the text window.
<h2>Constraints</h2> <h2>Constraints</h2>
<h3>General</h3> <h3>General</h3>
To create a constraint, first select the geometry to be
constrained. For example, when constraining the distance between
two points, first select those two points. Then choose the
appropriate constraint from the Constrain menu.
Depending on what is selected, the same menu item may generate
different constraints. For example, the Distance / Diameter menu
item will generate a diameter constraint if a circle is selected,
but a length constraint if a line segment is selected. If the
selected items do not correspond to an available constraint,
then MechSketch will display an error message, and a list of
available constraints.
Constraints are drawn in purple on the sketch. If a constraint
has a label associated with it (e.g. a distance or an angle),
then that label may be repositioned by dragging it with the
mouse. To modify the dimension, double-click the label; a text
box will appear on the screen, where the new dimension can be
entered. Then press enter.
<h3>Reference Dimensions</h3> <h3>Reference Dimensions</h3>
By default, the dimension drives the geometry. If a line segment By default, the dimension drives the geometry. If a line segment
@ -202,23 +417,133 @@
A reference dimension is the reverse: the geometry drives the A reference dimension is the reverse: the geometry drives the
dimension. If a line segment has a reference dimension on its dimension. If a line segment has a reference dimension on its
length, then it's still possibly to freely change that length, length, then it's still possible to freely change that length,
and the dimension displays whatever that length happens to be. A and the dimension displays whatever that length happens to be. A
reference dimension does not constrain the geometry. reference dimension does not constrain the geometry.
To change a dimension into a reference dimension, choose To change a dimension into a reference dimension, choose Constrain
Constrain -> Toggle Reference Dimension. A reference dimension -> Toggle Reference Dimension. A reference dimension is drawn with
is drawn with "REF" appended to the displayed length or angle. "REF" appended to the displayed length or angle. Double-clicking
Double-clicking a reference dimension does nothing; the dimension a reference dimension does nothing; the dimension is specified
is specified by the geometry, not the user. by the geometry, not the user, so it is not meaningful to type
in a new value for the reference dimension.
<h3>Distance / Diameter</h3>
This constraint sets the diameter of an arc or a circle, or the
length of a line segment, or the distance between a point and
some other entity.
<h3>Angle</h3> <h3>Angle</h3>
When two lines intersect, four angles are formed. The When two lines intersect, four angles are formed. These angles
opposite angles are equal; to change which opposite angle is form two equal pairs. For example, the pictured lines interesect
displayed, drag the label, and the arc will follow. If the wrong at 30 degrees and 150 degrees. These two angles (30 and 150) are
supplementary angle is displayed, then select the constraint known as supplementary angles, and they always sum to 180 degrees.
and choose Constrain -> Other Supplementary Angle.
<img src="/pics/tut-line-cross-angles.png" />
(Notice that in the sketch, three of the angle constraints are
reference dimensions. Given any one of the angles, we could
calculate the other three; so a sketch that specified more than
one of those angles would be overconstrained, and fail to solve.)
When a new angle constraint is created, MechSketch chooses
arbitrarily which supplementary angle to constrain. An arc is
drawn on the sketch, to indicate which angle was chosen. As the
constraint label is dragged, the arc will follow.
If the wrong supplementary angle is constrained, then select the
constraint and choose Constrain -> Other Supplementary Angle. A
constraint of 30 degrees on one supplementary angle is exactly
equivalent to a constraint of 150 degrees on the other.
<h3>Horizontal / Vertical</h3>
This constraint forces a line segment to be horizontal or
vertical. It may also be applied to two points, in which case
it applies to the line segment connecting those points.
A workplane must be active, because the meaning of "horizontal"
or "vertical" is defined by the workplane.
It's good to use horizontal and vertical constraints whenever
possible. These constraints are very simple to solve, and will
not lead to convergence problems. Whenever possible, define
the workplanes so that lines are horizontal and vertical within
those workplanes.
<h3>On Point / Curve / Plane</h3>
<h3>Equal Length / Radius</h3>
<h3>Length Ratio</h3>
<h3>At Midpoint</h3>
<h3>Symmetric</h3>
This constraint forces two points to be symmetric about some
plane. Conceptually, this means that if we placed a mirror at
the symmetry plane, and looked at the reflection of point A,
then it would appear to lie on top of point B.
The symmetry plane may be specified explicitly, by selecting a
workplane. Or, the symmetry plane may be specified as a line in
a workplane; the symmetry plane is then through that line, and
normal to the workplane. Or, the symmetry plane may be omitted;
in that case, it is inferred to be either parallel to the active
workplane's vertical axis or its horizontal axis. The horizontal
or vertical axis is chosen, depending which is closer to the
configuration in which the points were initially drawn.
<h3>Parallel / Tangent</h3>
In 2d (i.e., when a workplane is active), a zero-degree angle
constraint is equivalent to a parallel constraint. In 3d, it
is not.
Given a unit vector A, and some angle theta, there are in general
infinitely many unit vectors that make an angle theta with A. (For
example, if we are given the vector (1, 0, 0), then (0, 1, 0),
(0, 0, 1), and many other unit vectors all make a ninety-degree
angle with A.) But this is not true for theta = 0; in that case,
there are only two, A and -A.
This means that while a normal 3d angle constraint will restrict
only one degree of freedom, a 3d parallel constraint restricts
two degrees of freedom.
<h3>Same Orientation</h3>
A normal has a direction; it is drawn as an arrow in that
direction. The direction of that arrow could be specified by
two angles. The normal specifies those two angles, plus one
additional angle that corresponds to the twist about that arrow.
(Technically, a normal represents a rotation matrix from one
coordinate system to another. It is represented internally as
a unit quaternion.)
For example, the picture below shows two workplanes, whose
normals are constrained to be parallel:
<img src="/pics/tut-parallel-normals.png" />
Because the normals are parallel, the planes are parallel. But one
plane is twisted with respect to the other, so the planes are not
identical. The line on the left is constrained to be horizontal
in the leftmost plane, and the line on the right is constrained
to be horizontal in the rightmost. These lines are not parallel,
even though the normals of the workplanes are parallel.
If we replace the "parallel" constraint with a "same orientation"
constraint, then the two workplanes become identical, and the
two horizontal lines become parallel.
This is a useful constraint when building an assemblies; a single
"same orientation" constraint will fix all three of the imported
part's rotational degrees of freedom.
<h3>Comment</h3> <h3>Comment</h3>
@ -235,6 +560,11 @@
<h3>General</h3> <h3>General</h3>
To view a list of groups, go to the home page of the text window.
This is accessible from the link at the top left of the text
window, or by pressing Esc. To view a group's page, click on
its name in the list.
All groups have a name. When the group is created, a default name All groups have a name. When the group is created, a default name
(e.g., "g008-extrude") is assigned. The user may change this name; (e.g., "g008-extrude") is assigned. The user may change this name;
to do so, go to the group's page in the text window, and choose to do so, go to the group's page in the text window, and choose
@ -245,6 +575,10 @@
The group can be merged as union, which adds material to the The group can be merged as union, which adds material to the
model, or as difference, which cuts material away. model, or as difference, which cuts material away.
These groups also have a color, which determines the color of
the surfaces they produce. To change the color, click on one of
the swatches in the group's page in the text window.
The group's page in the text window also includes a list of all The group's page in the text window also includes a list of all
requests, and of all constraints. To identify a constraint or a requests, and of all constraints. To identify a constraint or a
request, hover the mouse over its name; it will appear highlighted request, hover the mouse over its name; it will appear highlighted
@ -252,11 +586,18 @@
text window. This is equivalent to hovering over and clicking text window. This is equivalent to hovering over and clicking
the actual object in the graphics window. the actual object in the graphics window.
<h3>Sketch in 3d</h3> <h3>Sketch in 3d</h3>
This creates a new empty group, in which the user may draw lines,
circles, arcs, and other curves.
<h3>Sketch in New Workplane</h3> <h3>Sketch in New Workplane</h3>
This creates a new empty group, similar to a new "Sketch in 3d".
The difference is that a "Sketch in New Workplane" also creates
a workplane. The workplane is created based on the entities that
are selected when the sketch is created.
A point and two line segments A point and two line segments
The new workplane has its origin at the specified point. The The new workplane has its origin at the specified point. The
@ -271,7 +612,7 @@
The new workplane has its origin at the specified point. The The new workplane has its origin at the specified point. The
workplane is orthogonal to the base coordinate system; for workplane is orthogonal to the base coordinate system; for
example, its horizontal and vertical axes might lie in the example, its horizontal and vertical axes might lie in the
+y and -z directions, or +x and -z, or any other combination. +y and -z directions, or +x and +z, or any other combination.
The orientation of the workplane is inferred from the The orientation of the workplane is inferred from the
position of the view when the workplane is created; the position of the view when the workplane is created; the
@ -281,12 +622,102 @@
If a part consists mostly of ninety degree angles, then this If a part consists mostly of ninety degree angles, then this
is a quick way to create workplanes. is a quick way to create workplanes.
The new group's associated workplane is automatically set to be
the active workplane.
<h3>Step Translating</h3> <h3>Step Translating</h3>
This group takes geometry in the active group, and copies it
multiple times along a straight line.
If a workplane is active when the step translating group is
created, then the translation vector must lie parallel to that
workplane. Otherwise, the translation vector may go anywhere in
free space.
The number of copies to create is specified by the user. To
change this value, click the [change] link in the group's page
in the text window.
The copies may be translated on one side, or on two sides. If
the copies are translated on one side, then the original will
appear to the left of (or above, below, etc.) all the copies. If
the copies are translated on two sides, then the original will
appear in the center of the copies.
The copies may be translated starting from the original,
or starting from copy #1. If the translation starts from the
original, then the translation will contain the original. (So a
1-element step will always produce the input geometry exactly.)
If the translation starts from copy #1, then the original is
not included in the output. (So a 1-element step makes a single
copy of the input geometry, and allows the user to translate it
anywhere in space.)
If the active group is a sketch (sketch in 3d, sketch in new
workplane), the the sketch is stepped and repeated. In that case
the user would typically draw a section, step and repeat that
section, and then extrude the step and repeat.
If the active group is a solid (extrude, sweep, lathe), then
the solid is stepped and repeated. In this case, the user would
draw a section, extrude the section, and then step and repeat
the extrusion.
In some cases, these two possibilities (extrude the step, vs.
step the extrusion) are equivalent. If the translation vector
isn't parallel to the section plane, then only the second option
will work.
<h3>Step Rotating</h3> <h3>Step Rotating</h3>
This group takes the geometry in the active group, and copies
it mutiple times along a circle.
Before creating the group, the user must select its axis of
rotation. One way to do this is to select a point, plus either
a line segment or a normal; the axis of rotation goes through
the point, and is parallel to the line segment or normal.
If a workplane is active, then it's also possible to select just
a point; in that case, the axis of rotation goes through that
point, and is normal to the workplane.
By default, three copies are created. If a different number is
typed in (to the group's page in the text window, as for Step
Translating), then the copies will be spaced evenly along a
complete circle.
To place the copies along less than (or more than) a complete
circle, drag a point on one of the copies with the mouse; all
of the rest will follow, as the step rotation angle is modified.
Constraints (for example an angle constraint, or a point-on-lie
constraint) may be used to specify the angle of rotation exactly.
THe step and repeat options (one side / two sides, with original /
with copy #1) are the same as for step translating groups.
<h3>Extrude</h3> <h3>Extrude</h3>
Before creating a new extrusion, the active group should contain
a sketch that consists entirely of closed curves. The extrude
group takes that flat sketch, and extrudes it to form a solid.
The sketch may be extruded on one side, or on two sides. If the
sketch is extruded on one side, then the new solid is either
entirely above or entirely below the original sketch. (Drag a
point on the new surface to determine the extrude direction,
and also to determine the extrude depth. Once the extrusion
depth looks approximately correct, it may be specified exactly
by using constraints. For example, select a line on the side of
the extrusion, and constrain its length.)
If the sketch is extruded on two sides, then the original sketch
lies at the exact midpoint of the new solid. This means that
the solid is symmetric about the original sketch plane. Later
dimensioning often becomes simpler when the part has symmetry,
so it's useful to extrude on two sides whenever possible.
If a workplane is active when the group is created, then the If a workplane is active when the group is created, then the
extrude path is automatically constrained to be normal to that extrude path is automatically constrained to be normal to that
workplane. This means, for example, that a rectangle is extruded workplane. This means, for example, that a rectangle is extruded
@ -299,12 +730,37 @@
could be extruded to form a parallelepiped. The extrusion has could be extruded to form a parallelepiped. The extrusion has
three degrees of freedom. This is not typically useful. three degrees of freedom. This is not typically useful.
By default, no workplane is active in a new extrude group. This
means that constraints will apply in 3d; for example, a length
constraint is a constraint on the actual length, and not on the
length projected into some plane. This is typically the desired
behaviour, but it's possible to activate a workplane in the usual
way (by selecting it, then choosing Sketch -> In Workplane).
<h3>Lathe</h3> <h3>Lathe</h3>
Before creating a new lathe group, the active group should contain
a sketch that consists entirely of closed curves. The lathe group
takes that flat sketch, and sweeps it around a specified axis,
to form a solid of revolution.
To create a lathe group, first select a line segment. Then choose
New Group -> Lathe. The line segment is the axis of revolution.
The section must not intersect itself as it is swept along the
curve. If the section crosses the axis of rotation, then it is
certain to intersect itself and fail.
<h3>Sweep</h3> <h3>Sweep</h3>
<h3>Helical Sweep</h3> <h3>Helical Sweep</h3>
This group sweeps a section along a helix. It might be used to
draw a screw thread, or a coil spring.
To create a helical sweep, first draw the section to be swept
along the helix.
<h3>Import / Assemble</h3> <h3>Import / Assemble</h3>
In MechSketch, there is no distinction between "part" files and In MechSketch, there is no distinction between "part" files and

16
draw.cpp
View File

@ -37,9 +37,11 @@ void GraphicsWindow::MouseMoved(double x, double y, bool leftDown,
// When the view is locked, permit only translation (pan). // When the view is locked, permit only translation (pan).
if(!(shiftDown || ctrlDown)) { if(!(shiftDown || ctrlDown)) {
offset.x = orig.offset.x + dx*projRight.x + dy*projUp.x; double s = 0.3*(PI/180)*scale; // degrees per pixel
offset.y = orig.offset.y + dx*projRight.y + dy*projUp.y; projRight = orig.projRight.RotatedAbout(orig.projUp, -s*dx);
offset.z = orig.offset.z + dx*projRight.z + dy*projUp.z; projUp = orig.projUp.RotatedAbout(orig.projRight, s*dy);
NormalizeProjectionVectors();
} else if(ctrlDown) { } else if(ctrlDown) {
double theta = atan2(orig.mouse.y, orig.mouse.x); double theta = atan2(orig.mouse.y, orig.mouse.x);
theta -= atan2(y, x); theta -= atan2(y, x);
@ -50,11 +52,9 @@ void GraphicsWindow::MouseMoved(double x, double y, bool leftDown,
NormalizeProjectionVectors(); NormalizeProjectionVectors();
} else { } else {
double s = 0.3*(PI/180)*scale; // degrees per pixel offset.x = orig.offset.x + dx*projRight.x + dy*projUp.x;
projRight = orig.projRight.RotatedAbout(orig.projUp, -s*dx); offset.y = orig.offset.y + dx*projRight.y + dy*projUp.y;
projUp = orig.projUp.RotatedAbout(orig.projRight, s*dy); offset.z = orig.offset.z + dx*projRight.z + dy*projUp.z;
NormalizeProjectionVectors();
} }
orig.projRight = projRight; orig.projRight = projRight;