Convert 3ds to solidpart in SW

How to convert 3ds from 3DMax to solidpart in SW and make it smooth?
The convertion with the ShapeWorks program makes it look made of
polygons.

 

That's because that's all you have in 3DS, polygons. The smoothness, in 3DS,
is achieved graphically. A 3DS file is equal to the display list in SW, just
a bunch of shaded triangles. There is no mathematically exact data.

You can't really make something from nothing. There are a couple of programs
that "claim" they can drape NURBS surfaces over a 3DS polymesh, but you'll
end up with an approximation of an approximation. OK if you're just using
objects for a rendering scene. Terrible (and not worth the time and effort)
if you're using it for product design.

Mark

 

3ds meshes have smoothing groups that define sets of polygons that are
a continuous surface. I find a lot of .3ds files that don't have
smoothing groups defined, so you end up with an entire mesh that looks
tesselated. I don't know if ShapeWorks will read in the smoothing
groups (I am usually going out of SW into 3ds max), but if you want to
send me the .3ds file I could at least check to see if there are
smoothing groups defined.

Joel

Joel Howe
http://www.frameworkmedia.com/

 

Smoothing groups is a propriatery "algorithm" inside 3DS, not a graphical
"object"

Some things, like lights and textures, are tranportable to other
animation/rendering programs, like Maya, but not SW.

In this respect SW is simple. You have hard exact geometry that contains
real mathematically defined curves and faces. This is tesselated (diplay
list) and the tesselation is smoothed autmatically by OpenGL. The underlying
3D object is really smooth

With 3DS you have tesselated objects to which you apply smoothing algorithms
to make the object "appear" smooth. The underlying object is tesselated.
This is usually OK because the intent is to create animations or renderings.
The program "is not" a design tool.

SW reads in "Geometry", not attributes. If the geometry exsists in the
originating system as B-rep solids (STEP, X_B, SAT, or IGES-186), then
that's what you get.

If it exists as a polymesh, (VRML, STL, etc) then that's what you get.

We've had Max as long as we've had Solidworks. The only usefull direction is
SW to Max for special renderings or animations. Max to SW is a complete wast
of time and energy. The only solid design product I've ever used that can
read in 3DS, with all the attributes, Is Iron CAD. Even then, you were very
limited as to what you could actually do with the data. With Solidworks,
it's like apples and oranges.

Regards

Mark

 

Mark,

Everything that you write is correct, but doesn't really answer the
person's question.

My thought was: Since SolidWorks does have to tesselate a model, or
convert it to a polygonal mesh, for display on the on the screen, then
it does make sense that it has some capability to interpret what 3ds
max calls smoothing groups. Assuming this is true, then maybe
ShapeWorks can keep track of this. Smoothing is ubiquitous in all
polygonal modelers, so maybe a properly smoothed model will help
improve the display of the object in SW. It is also safe to assume that
PhotoWorks (which is really mental ray) is creating a polygonal mesh to
render and would recognize smoothing.

I think you are correct, assuming someone has access to 3ds max. If
they do not, I have see plenty of situations where you might want to
bring 3ds objects into SW for reference. Human models for
ergonomics/medical devices, automobile exteriors for showing placement
of system components, etc. You are right that the 3ds files or any
other tesselated formats are not really usable for actual design parts,
but they are great for reference.