Hello!

New Houdini-using Department. here!

We're at a manufacturing firm just outside London, making product animations.

The Design team use Solidworks, with objects using fairly heavy Solid Modelling (new area for me) which amounts to Nurbs as far as I can tell.

If anyone can help me hammer out some issues we're having, there's a large number of beers in it for you.

I suspect this is largely a set of challenges where the world of largely solid-modelling meets largely surface-modeling packages.

At present, we've tried the following:

Solidworks > FBX export via Simlab Plugin > Houdini
Works/renders ok but offers no real control over how the shape is polygonised into triangles.
(And while the Normals included look ok, as soon as a bump or displacement shader is added the triangles show up and can't easily be proceddurally consolidated / smoothed / re-meshed).
No Nurbs-like objects appear to be retained.
Nice groups and colouring however.

Solidworks > IGES export > Houdini
Opens but with a hideous amount of control points in places, and brings in a few unseen guide shapes which when deleted take those surfaces with them. Very heavy in the viewport.
Tried lots of export options but the Sketches (guide/boolean geometry) doesn't get trimmed out properly.

Solidworks > STL file > Houdini
Normals and fairly messy polygonisation still occurs.
No groups or material groups are included.

Solidworks > C4D > OBJ
Groups and material groups are lost.
Same lack of control over how polygonisation / triangulation happens.
Similar to STL import.

As there's quite a few objects to get through over the coming months, I'm seeking a method which doesn't involve a tone of clean up or hairy remodelling of things.
3rd Party conversion or Re-meshing software is a possibility, but I thought I'd ask the forum if anyone has any recommendations before we start building a frankenstein pipeline to deal with it all.

Pete

Do you have a simple example of ‘Solidworks > FBX export via Simlab Plugin > Houdini’ you can upload.

Surely the triangles can be fixed - could be some winding order stuff going on..

Thanks!

In terms of third-party solutions, you might want to try PolyTrans as a go between: http://www.okino.com/solutions/solidworks.htm [okino.com]
Personally, I've never used them but these guys have been around for a long time.

Hello Marty and Edward,
Thanks for replying. On the FBX/poly side, we've found that it might be possible to set the outgoing mesh density using a native parameter in Solidworks before the plugin Honks it out.
This is making smoothing and fixing normals later on a bit easier, but still leaves wierd areas that need manual attention via consolidating points and Cusping.

Our holy grail is still Nurbs I suppose, as we may have to work on hundreds of these, - and the more animating the team can do as opposed to re-modelling the better.

Yesterday Polytrans and Rhino seemed to import IGES ok, but the interpretation in Houdini still left objects looking like porcipines or having odd shapes that, once deleted, took essential areas with them.

I'll try to send you a file which is not bound commercially, but I may have to resort to screenshots.

Pete

From reading the PolyTrans website, I think they recommend their direct SolidWorks importer, not via some other format:
http://www.okino.com/conv/imp_sw.htm [okino.com]
However, it looks like you need some extra add-in pack for extra money to get that.

Pete, I've just started exploring the use of Houdini along side Solidworks and have an effective (though not free) solution.

Check out Moment of Inspiration (http://moi3d.com/). [moi3d.com] It is a former Rhino programmer who decided he could do a better (simpler) job of nurb modeling system…and I'd have to agree.

Where MOI comes in is that you can bring .step files into MOI without errors in surfaces etc (at least I've yet to have any) delete anything you didn't want as well as other manipulation as necessary and then export to FBX (I tried OBJ but every part came in as a single geometry). The magic is that you can adjust, with full on screen preview, how the surfaces are carved into polygons with several very powerful options.

It has worked great for me and gives you a very nice nurbs based modeler on top of it…and I think it is cheaper than PolyTrans (though I'm not certain).

Hope this helps.
-GW

Hello GW!
That's great to hear! And thanks for replying!
I'll try that asap and get back to you.

Pete

Hi guys,
My name is Stu, currently working with Pete (the OP)

GW - I've been trying that MOI today. As you mention, it gives a few nice options for the outgoing tessellation. Still running into issues when trying to give the model certain shaders, typically ones with bump maps, showing the triangulation of the mesh. ~Is this something you've come across yourself? (pic attached)

Many thanks,
Stu

Stu;

Wow, that is wild!
I'm actually very much in the same boat as you…just dipping into Houdini, but I've not come across this issue. I've not tried applying bump maps yet either though, but I have added “noise” to a glass material and the results have been good.

I also did not output triangles when I tessellated my export. I used N-gons which came into Houdini just fine and have yielded (so far) smooth rendered results with glass and “clay” materials.

Let me know how you got to this picture and I'll see if I can get similar results. (Us Solidworks folks got to stick together!)

-GW

I'm actually running into a similar issues with Bump Mapping and Triangles from imported models.

Your use of MOI is interesting, it is something I'll have to look more deeply into. I tried it for my current project but found the STEP file I used was to complicated or had too many parts as it would just hang when importing. I've had to use 3DS Max to import STEP files, which are then exported via obj for Houdini.

Maybe we can log it as a bug.

For the triangles, can you please try setting the Tangent Style from Use Geometric Tangents to another setting int the Surface Model Vop.

Just tried it, saw no visible difference. Thanks though!

I submitted this item and a hip file to SESI for review. #20347

Cool - please keep us posted with the solution.

Thanks!

sry for the late reply, had to leave the office early yesterday to go househunting

After a bit of faffing about playing with the settings, I got a fairly decent mesh out of MOI. I needed to do a little cleaning up in MOI, delete a couple of bits. The bump map issue is still happening, however, I made a VOPs shader yesterday with just a basic bump and it looked fine, so I'm wondering if it's an issue with the shader out of the box

Gyroscope - Did you build your shader, or manipulate a mantra/other shader? (I made mine with a mantra shader)

MartybNz - I tried changing the tangent style - didn't make any difference

I'm going to build on this custom shader today to see how far I can push the bumps before anything horrible happens. Will keep you updated

Would it be possible to cut a bit of the mesh off and post it up? Just the smallest bit with the bad triangle so we can test.

No problems if not - always fun to solve these challenges

Can you show how normal looks like in that geo?
Bump is that texture that depends on UV map?

MartybNz - Ive attached a HIP file with a piece of the geo. It contains 3 shaders, 2 of which I started with mantra shader and manipulated, the “myShader” I built in VOPs. I've left it on ‘anthracite’ shader which is the biggest culprit for showing the tessellation.. ‘cast iron’ looks ok, but push some settings a bit more and you begin to see the same issues.

As far as ‘myShader’ - seems I can push it pretty far. It has a bump noise.. I tried cellular cracks and ended up with the visible triangles again

SreckoM - Ive attached an image of the normals.. they seem fine to me. The bump is a bump noise in VOP, not an image. I definitely do NOT want to be messing with UV maps on these meshes!

oops.. im working from an FBX file, so you're probably missing the geometry!
(zipped bgeo attached)

Tell a lie - my ‘myShader’ does work way better, but still not good.. the back shows some lovely artifacts

This is what I get.


1. Clean existing normals, by adding Clean SOP and check remove attributes. You can be more specific and clean just N attribute.
2. Add Vertex SOP and under Normals choose Cusp Normal and set angle 40. You can play with angle here.
Model is not perfect so you can no get perfect edges here.

And where you had main problem is under Noise you Amplitude was 63, not sure why. Here is Noise setup I used.