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OBJ to Solid converter

Posted: Thu Apr 17, 2008 4:27 pm
by mtripoli
Anyone know of a good mesh to solid converter? OBJ > IGES? OBJ to SLDPRT (Solidworks) would be great...

Posted: Thu Apr 17, 2008 4:59 pm
by Eric Lagman
Rhino has a mesh to nurbs function which you can then export out as iges. I dont know how well it works though.

If it is a quad mesh that was created in a 3d program like cinema 4d or Max
there is a plugin called T-splines for rhino that will import an obj file into rhino very nice and give you a good clean nurbs surfaces to export out as solids.

Posted: Fri Apr 18, 2008 1:19 am
by polynurb
the rhino _meshtonurb command works well for meshes that don`t exceed a certain polycount (~100.000) , as you get a trimmed surface for every triangle. (memory issues; -but you could split the mesh in parts before conversion if it is very big)
If you are dealing with geometry containing planar areas use _mergeAllFaces
to unify coplanar mesh faces after conversion.

asfaik, iges can`t transport true solid data, as what is a closed polysurface in rhino gets exploded during export to iges; so you would need to join it back together in the other application.

Posted: Sat Apr 19, 2008 10:51 pm
by val2
mesh to solid by sycode
http://www.sycode.com/products/mesh_to_solid/index.htm
does it.

Val

Posted: Sun Apr 20, 2008 12:58 pm
by Polyxo
Conversion of organic shapes in a poly by poly (meshToNurbs) manner is pretty much pointless for most scenarios. The result is your rough basemesh with only meshfaces replaced by trimmed Nurbs faces. There's no options to smooth these Nurbs patches.
The only application where this aproach could make sense is when the mesh is unsubdivided and has no bevels - geometry Sketchup typically creates.
These meshes are easily convertable to Nurbs (even automatically at Import inside Rhino). The best smooth conversion of lowpoly meshes to Nurbs I know of is Tsplines. The Sycode product cost a lot of money and works only on objects which are also extremly easy to reverse-engineer by hand. In fact the objects shown on the website could be saved as Sketchup files and converted at import. With the same poor result as shown on this website...

Holger

Posted: Tue Apr 22, 2008 7:15 pm
by mtripoli
Thanks for the responses... I tried the Sycode product and choked it every time. I go one result but as you say I could have reproduced it in Solidworks in about 15 minutes. I was hoping to find something that worked ok; there are tons of 3D models out there that would be cool to use as "filler" in scenes to make them more realistic... oh well....

Posted: Wed Apr 23, 2008 8:44 am
by NicoR44
I think T-Splines is the ultimate proof that you can convert an object mesh to nurbs.
Some of you might have seen my stick in the WIP section, made in Silo, exported as unsmoothed mesh and converted using T-Splines in Rhino:

Image

Image

Image

Image

Image

Posted: Wed Apr 23, 2008 9:45 pm
by val2
I'm sure tsplines is great. the problem with it is it's not a stand alone product that I can see (or is it?) so you need maya or rhino first and then you have to shell out more money for it to do a conversion.

I think what mtripoli was asking for was a stand alone. I've been looking for a good mesh to solid converter as well.

I just found Reserect online.
http://www.ghost3d.com/gt_ResErect_uses.htm
does anyone have an opinion about it? Like does it do what it says it does?

Val

Posted: Wed Apr 23, 2008 11:03 pm
by glypticmax
I've done some T-Spline mesh to nurbs conversions and they work very well. I believe there is a 20,000 poly limit though. Very low for most of my needs.
At this time I think T-Splines is only a plug for Maya and Rhino.
You might look at PolyTrans. My knowledge of it is sketchy, but it is basically a tool for converting between 3D formats. And I think its not cheap.
Good luck.

Posted: Thu Apr 24, 2008 1:43 am
by polynurb
..well ture that Tsplines has a limit on polycount at the moment :?

.. but if you just want to convert the geometry (no editing of the shape)
nothing keeps you from splitting the mesh into parts (eg. _ExtractConnectedMeshFaces ) before Tspline conversion, and then join the derived nurbs surfaces back into a solid.
And tSplines does not just convert, it actually reestimates surface curvature into a genuine nurbs surface (see Nico's zebra shade), and for that capability it's price is low.

Posted: Mon Apr 28, 2008 7:26 pm
by Jakakadave
Yep, I can do that, but should I tell I wonder?

I had to work out how to do it when I did the Damien Hirst Skull (Shameless self aggrandisement).

You can do the following....

Import your mesh to Raindrop Geomagic Studio.

Convert to surfaces using the tools found therein (can be fairly time consuming if you have very complex or dirty geometry).

Save as IGES.

Import to solidworks

Hey presto - tis done!

Posted: Mon Jun 02, 2008 4:15 am
by val2
I know this is an old thread but it has taken me this long to figure it out.

I am using 3dsmax.
I downloaded splineCagify from scriptspot turned a mesh into a spline then applied a surface and then converted it into a nurb. you can then export it as a .IGS file

costs no money.

I have been reading stacks of forums with piles of people with the same problem. As long as you are doing low poly modeling and with a little tweak on the spline here and there, you get a really nice out put.

Posted: Mon Jun 02, 2008 3:03 pm
by mtripoli
Jakakadave wrote:Yep, I can do that, but should I tell I wonder?

I had to work out how to do it when I did the Damien Hirst Skull (Shameless self aggrandisement).

You can do the following....

Import your mesh to Raindrop Geomagic Studio.

Convert to surfaces using the tools found therein (can be fairly time consuming if you have very complex or dirty geometry).

Save as IGES.

Import to solidworks

Hey presto - tis done!
I've tried GeoMagic in the past and it was less than ideal (in fact, I had the rep at my office and he got so frustrated after a couple of hours that he just gave up).

I have PolyTrans; it simply doesn't do this conversion.

I've looked at a bunch of different ways of doing this. I *was* looking for a stand-alone package that could do this without much sweat. It looks like my *old* way of doing it is the best; just rebuild the model from scratch in Solidworks.

Posted: Wed Jun 04, 2008 3:31 am
by b-kandor
Also, if you have sw-premium it can open a mesh and convert it with the scan to 3d tools, they have advanced pretty well in 2008. Although I use rapidworks (similiar to geomagics) to do this.

Or in Catia they have a module called 'imagine and shape' which is a sub-d modeller that output nurb surfaces directly into catia.

Years ago, I used a standalone converter that was a dos program - no graphic output at all, you pointed it to an stl file and it created an iges for you - worked very well, but I can't remember the name (this was a mid - 90's thing)

Kandor

Posted: Wed Jun 04, 2008 4:16 am
by val2
I think you might be talking about "Poor Persons Outline for Working in 3D"
http://home.austin.rr.com/reubenrachel/ ... tml#output

It works in in xp32