Body object to NURBS or Patch

[newfriend]

Good day, looks like I'm the first one who asking about it. I have an igs (STEP) file, which has been imported to the Max scene. As I can see, the imported object looks like it was made by NURBS, which is good for me. However, it identified as a Body object, which is bad. I'm trying to convert it to NURBS or Patch to keep smooth shape with less than quadrillion polygons. But as I can see conversion available only to mesh and poly. Please, advice, how to convert and edit body object to NURBS or patch? Thanks.

[leeminardi]

See if the follow yields what you want. Convert the imported NURBS object (from an igs file) to individual NURBS elements by selecting the object and then go to the Modify tab.  Click the Elements button under Object Parameters / Explode into Separate Object.

[newfriend]

Hi, thanks for reply. I did as you said. But result is the ckracked body object. It's mean in first step I had 1 body object and now I have 101 still(!) body objects. What I need is to convert body object to NURBS or Mash. This option is unavailable for single and for separated body object. Maybe it is inpossible at all than?

[Anonymous]

Hi NewFriend.

I import IGS models from Rhino every day and don't experience any real problems. Unwrapping UVs are an issue, but I split the object in Rhino before importing.

As tessellation happens at render-time for both Solid Body Objects and NURBS, can I ask why you need to convert?

If it's a smoothing concern, have you first welded all edges into a single element and adjusted the Rendering Approx and Viewport Display?

[newfriend]

I have an object of phone device. It was made in some application (don't know where). When I try to import it directly to Max - nothing happens. It took about 1-2 hours and then nothing. Just empty space. So, I'm opened the Rhino and import it there in 2 min. After that I just save as this file to the same format and then import it to Max again. Now it's works. I can see the phone structure and now need to build the render.

Main problems are: the size and selection. It's a complex object and it's move slowly, I decide to remove some part which won’t be seen in a render and combine others, but I can’t edit this body object. Only poly is available with quadrilion segment I don't want to see while editing. Also editing in NURBS or patch is easy for me.

The other problem – this body object is hard to select. When I click on the surface nothing happens like it have inverted normals (which I can’t invert in body mode). So, I need to target to the edges. I can’t normally select and edit this body object, that’s why I need to convert it to NURBS or patch for further easy editing.

If you wish, I can provide this source file, but be aware it's about 200 MB.

[Anonymous · Accepted solution]

Aaah, OK. Max isn't an out-and-out Solid Body editor, but it isn't the end of the world.

It sound like an option was left unticked with the original file export, which is why Max is struggling to import the object, but if Rhino has rectified that, then it's not a problem anyway.

If you're using Max purely for animating / rendering, can you delete the unneeded parts in Rhino first, before importing?

Back in Max though, I found the best way to work is to select the object in question, and under Viewport Display Settings (in the Modifier tab), select the Mesh radio button, then turn the quality to Coarse. If the mesh is still too dense in your viewport, you can adjust the Face Distance % to a higher number. You see live feedback when you adjust.

Obviously, you don't want it render like that, so make sure in Render Approx, that Use Viewport Mesh is unticked and Production is selected. Again, you can make the render tessellation even more fine by adjusting numbers underneath.

So even though Max doesn't have a convert-to-NURBS option (that I'm aware of), the above should make selecting the object easier (as you can see the edges to click on) and navigating the viewport and moving the object should be far more smoother.

There may be plug-ins that can convert, like Power NURBS Pro, but I genuinely don't need to.

[newfriend]

Hi, again. Yes, I'm using only Max. Sad to say, but I have only a trial Rhino (install to convert this file). I have no idea how to use it and those few minutes when I tried to edit model in Rhino was a nightmare for me. That’s why I just saved as this file and planned to edit it in Max later. Sure, it’s a matter of choice where and how to edit. But as for me Rhino is new software to study and to buy (not sure I really need it). Now I understand there is no much choice. If Max can’t convert body to NURBS only Rhino or Power NURBS left. Have to think about it. However, thanks for your advice!

[Anonymous]

No problem. Glad I could (kind of) help.

The only other thing you could try is to select the object and choose Mesh and adjust its density (as above), then click on Element under Editable Body Object in the Modifier tab, and delete the unneeded objects. Not sure if that's what lminardigmail meant above, but you wouldn't be exploding the object into 101 separate objects. All is retained as a single object, but you've simply deleted at a sub-object level.

Hope you find a workaround. Best of luck.