I currently deal with a lot of engineering data from Alias Studio Tools and Rhino, and I use PowerTranslators to get it into Max.
When I render a scene from a standard max camera or a perspective view, the objects are tesselated depending on their distance from the camera, so they always appear perfectly smooth.
However, when using the new VRayPhysicalCamera or when overriding the camera in the render settings, it doesn’t seem to tesselate them, and just renders the coarse models I see in the viewport.
I don’t know if this is a VRay problem or a PowerNURBS problem, or just something I’m going to have to put up with, but it’d be nice to be able to use the physical camera with nurbs data if at all possible.
Is there anything I can do, short of converting every surface in the scene to an editable poly, to get them looking smooth through the physical camera?
Well then turn off viewdependent mesh. Make tesselation constant. Or you can leave viewdependant option, but increase “Max Edge” to… mmm 0.7 Play around it…
Give me a little while, and I’ll render off an example or two and find somewhere to upload them.
Paul:
Thanks for the suggestions.
I’ve tried checking ‘render viewport mesh’, having gone through every object and setting the viewport display settings to far higher values. But this means (a) I’ve got to go through loads (sometimes hundreds) of objects in each scene just to use the vray camera and (b) it slows the viewports down to a crawl.
Also, importing them as a size-dependant mesh still seemed to create quite blocky meshes when rendered.
Your suggestions would be really helpful in a small scene with only a few nurbs objects in it, but if I’m working with the cad data for a production car, for example, I don’t want to have to go through every object and set the tesselation values for each one individually, because it would take me days. I’m trying to write a maxscript to do it for me, but I’ve never really done any scripting before, so I’m not getting anywhere fast.
It all seems like a lot of work just to use a camera with a few more features than the standard one, but it would be nice to be able to.
Well in this case - I think powernurbs can handle iges groups (just don’t remember). Group your objects, and import 'em in groups, I think there won’t nessesary to adjust EVERY object. Instead - every group
Be easiest to get Vlado to make the vrayphysical camera class like a max camera or to get the powernurb guys to allow any object to be picked as the tessellation node.
well…read the docs of powernurbs no need to use the viewport meshes. you can tune rendertesselation without using view dependant tesselation. if you switch to size dependant tesselation you have to retune your tesselation settings. And you can do that on all of the objects at once. Simply select them all and use the “PowerNrb” button in the Powernurbs Tools 1. (NOT the PwrEditNrb ) Then the navigator pops up and generel settings in the modifier rollouts. setting options there will change all selected objects. I’d suggest playing with ONE object first tho to find good settings, as it can be pretty slow otherwise.
So, does the Vray camera use the viewport or the render mesh settings for rendering? I haven’t been able to use 1.5 yet (long boring story) and see for myself.
It uses the render mesh settings.
It just doesn’t appear to take the camera position into account when it renders with view-dependant tesselation, so the objects close to the camera aren’t tesselated any more than those further away.
I’ll look into it, but it may be that this is for the PowerNURBS guys to fix. When using regular NURBS in 3dsmax, view-dependent tesselation works fine with VRayPhysicalCamera. I suppose that PowerNURBS may have been specifically coded for the standard 3dsmax camera.
There was indeed a problem with the VRayPhysicalCamera which is corrected for the next RC. Hopefully, it will fix this problem too.
The problem with view-dependant tesselation also occurs when overriding the FOV of a max camera in the render settings. Will this be fixed when the VRayPhysicalCamera is fixed?
I don’t know - I just know that there was a problem and it was fixed; I’m not sure it will actually fix the PowerNURBS issue at all until I test it here.
no need to use the viewport meshes. you can tune rendertesselation without using view dependant tesselation. if you switch to size dependant tesselation you have to retune your tesselation settings. And you can do that on all of the objects at once. Simply select them all and use the “PowerNrb” button in the Powernurbs Tools 1. (NOT the PwrEditNrb 
) Then the navigator pops up and generel settings in the modifier rollouts. setting options there will change all selected objects. I’d suggest playing with ONE object first tho to find good settings, as it can be pretty slow otherwise.