Can SW use one moving part to shape another...?

Can SW 2007 use one moving part to shape another...? In other words
can collision or conflict be used to have one of the parts modified to
the profile of another of the sliding parts? And if so, can anyone
give a quick intro on how it is done? Thanks.

 

You really want something like a CAM program for this. I have done
something like it with a really dense pattern. Performance suffers.

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Basically it's a "swept volume" problem, which is still a research
topic and isn't available as a general function in any CAD on the
market today : you'd want to make a sweep of the tool volume along its
path (very hard in the general case), then subtract this body from the
part body (easy).

For "simple" cases, such as tool with axial symmetry (mill) moving
along a simple XYZ trajectory, you could create multiple sweeps (to
avoid self-intersection problems) along the path using either the mill
profile sketch or a projection of its silhouette on planes orthogonal
to the trajectory, then add the tool volume itself at trajectory
corners to obtain a swept volume. (I wrote a macro that helps doing
this for a customer for an engraving problem ...)

The solution used in CAM simulation typically uses "voxels" : space is
divided in very tiny cubes, smaller than a pixel on screen. Each voxel
has a value to describe void (0), tool(1) or part (2). As you move the
tool, part voxels are replaced by tool voxels, which become void once
the tool has moved away. An algorithm called "marching cubes" is used
to represent smooth surfaces in screen resolution, but internally,
there is no way to obtain a geometrically precise, smooth surface as
required by a CAD program.

I tried a combined approach on SolidWorks by subtracting the tool
volume to the part at each tiny step of the trajectory. It works, but
creates a colossal number of jigsaw looking tiny faces resulting in
huge and unusable files...

 

Just remember there already was a thread on this topic : check "sweep
a volume" or
http://groups.google.com/group/comp...3616c?lnk=gst&q=swept+volume#169107674b13616c

 

www.machineworks.com

Used by most CAM programs.

You can save the solid cut part rendering as an .stl

Jon Banquer
San Diego, CA

 

It's basic but, In SW2008, there is a new Cut Sweep Volume option
(can't do a sweep volume,.. ah the consistency!?!?) but... it's
limited to just a revolve using analytical curves.

Otherwise, as was suggested,.. you can either do a dense pattern of
the body or... more work,.. use patterned bodies along a path and
reference the edges/vertexes to do a smoother loft... either way,..
not pretty or fun. It depends on the clearance/tolerance your
after?

..

 

Sort of depends on being able to project the moving shape onto
a plane perpendicular to it's path and then on the trajectory - not hard
for lines & arcs if swept profies are supported well, iffy for spline
curves, twisty stuff. In theory.

 

Cloud of points ==> surface approximations.
But the voxel stuff is more image processing related I think
as the real CNC stuff usually outputs things like linear moves,
circular moves & axis vectors. It also assumes a tool circularly
symmetric about it's axis vector (milling, not lathe) which may
impose some unwanted constraints on this specific matter
(as well as using up a degree of freedom).

 

Perhaps not .....
http://www.cgtech.com/usa/cgtech/partners/

Good example of "how it's done" you say?

Consider a trapazoid with a depth of 6 (Z)
as your moving part:
http://kspark.kaist.ac.kr/Aesthetic Engineering.files/Area Centroid.files/Trapazoid0.gif
Pretty simple .... but no way will machineworks.com help in the general case
even for this simple tool solid.

LOL ...

Clueless wrong answers yet again.
No 3D CAD background as well as no actual CAM I suppose.

 

BTW, Computervision's ASD (Advanced Surface Design) used (CADDS IV & IV-X
on their CGOS platform) to come rather close to what might be needed though it
produced Bezier surface geometry.

 

You just reminded me of something I tried in 1998.

Patterned a tool in an assembly then joined it into a part. But as
Philippe has noted, performance may suffer.

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