render to UV space

[Gary Jaeger]

I’m not sure I’ve thought this through completely, but is it possible to render to UV space with vray? For instance, let’s say I’m rendering a sphere. But what I want for my final render is the unwrapped UV render as seen from the POV of the camera. Does that make sense?

Gary Jaeger // Core Studio
249 Princeton Avenue
Half Moon Bay, CA 94019

650.728.7957 (direct)

650.728.7060 (main)
http://corestudio.com

[Ian Waters]

Hi Gary,

To do normal texture baking it’s:

Vray Common > Baking Engine Settings > Texture baking.

Though I’m not sure exactly what you mean by from the POV of the camera?

Ian

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[Mark Serena]

You can use soup to unwrap from UV space to 3d space and render that mesh.

[Gary Jaeger]

Thanks Ian and Mark. Actually what I’m looking for is the equivalent of nuke’s scanline render UV projection mode. I don’t want to change the mesh, since that would change the render. Imagine a lit sphere. With the nuke UV projection, you can render to 0-1 space with all the lighting intact. Sort of how you can render to cubic or spherical projection with vray, I just want to render to UV projection. Can I make attachments here? let’s see…

Gary Jaeger // Core Studio
249 Princeton Avenue
Half Moon Bay, CA 94019

650.728.7957 (direct)

650.728.7060 (main)
http://corestudio.com

[Gary Jaeger]

btw, you can do this in post with RevisionFX ReMap Inverse UV, but I’d like to see if I can do it natively. Without baking if possible.

Gary Jaeger // Core Studio
249 Princeton Avenue
Half Moon Bay, CA 94019

650.728.7957 (direct)

650.728.7060 (main)
http://corestudio.com

On Sep 21, 2015, at 6:35 AM, Gary Jaeger <ga...@corestudio.com> wrote:

Thanks Ian and Mark. Actually what I’m looking for is the equivalent of nuke’s scanline render UV projection mode. I don’t want to change the mesh, since that would change the render. Imagine a lit sphere. With the nuke UV projection, you can render to 0-1 space with all the lighting intact. Sort of how you can render to cubic or spherical projection with vray, I just want to render to UV projection. Can I make attachments here? let’s see…

<uvprojectionrender.jpg>

[Tim Leydecker]

That nuke render UV projection mode is just a fancy way of saying "bake my camera projections down into this UV set".

Most likely originates from matte painting compositing workflows, projecting footage stuff on cards
and then wanting to clean up the result further by painting over the baked down image.

A bit more info in the Maya docs about baking (in mR) can be found searching for

Lighting/shading > Batch Bake (mental ray)

But  the sphere you´ve picked to test is a special case, so it´s hard to tell if you try to reverse engineer
a lighting probe shot on set, go between a MatCap Style  and spherical projection or just got confused
by the naming of the node?

I haven´t used VRay in a while (unfortunately!) but afaik it supports baking stuff to texture.

Or do you want to use some sort of UV remapped magic in comp, swapping out a texture after rendering?

Or are you just intrigued?

http://www.nukepedia.com/written-tutorials/understanding-uvmaps-warping-with-stmap-pt-1
http://www.nukepedia.com/written-tutorials/understanding-uvmaps-warping-with-stmap-pt-2


Cheers,

tim

[Gary Jaeger]

Thanks Tim. No, it’s not just me being intrigued :). We’re working on some projection mapping stuff, and we’re able to deliver a model with UVs into the projection system, which can then figure out the warping and project the material properly. So the ability to deliver the renders in UV space is key. Like I say, we can use the InverseUV ReMap, but since Vray does some many other fancy camera projection renders it seemed like it might be able to do this one. I know about baking, and I’d rather not since it’s another step, but might be unavoidable. 

Gary Jaeger // Core Studio
249 Princeton Avenue
Half Moon Bay, CA 94019

650.728.7957 (direct)

650.728.7060 (main)
http://corestudio.com

[Tim Leydecker]

Hi Gary,

now I am intrigued. Sounds like a nice even if complex project.

In terms of delivering renders mapped to a 3D space, I worked for a project where
a live stage would be flooded with a bunch of beamers, shining on big sail like
elements that could be moved during segments of that big event automobil show.

Setdesign had these elements provided, each beamer projected surface was unwrapped
and this UV set was then also the projection sheet for the realworld set, the stagecrew
using it to cleverly split and array multiple HD1920 inputs across different beamers and
angles required to make reach all areas of the stage.

All I did was create some 3D content, rendering through cameras set in Maya and handing
off that content to a Nuke artist, who would use the set elements´s UVset to project onto
(using Maya´s cameras) and then bake that to multiple outputs, each a HD1920 format
using Nuke´s "render UV projection".

Long story short, it was found best to do the actual re-mapping in Nuke because any kind
of animation or postprocess could be piped in between as needed, while 3D content could
be created using a pretty reliable view through a variety of "spectator" perspectives, instead
of having to "look through" something like a spherical perspective mapped output directly.

Cheers,

tim