Vray motion blur with maya ramp texture - not working?

[seandunderdale]

Ive attached a simple scene from a project I recently worked on, but I found during it, I was using ramps to control effects in a major part of the project, but that motion blur was not applied to their animation. It seems pretty crazy that a animated ramp wont get affected as Im sure people use animated ramps to create effects all the time. I hope there's just something Im doing wrong. Ive set it up so it renders one frame with motion blur on. There is an animated object, which is blurred, and the circular ramp effect, which does not blur. The ramp looks the same in IPR as it does in render (since ipr doesnt support motion blur), but the geometry is blurred in render.

V-Ray 5 for Maya, update 2.2

(v5.20.02, revision 31334 from Mar 31 2022)

[hermit.crab]

I think motion blur on textures works only if you key the functions of the 2d/3d placement.

[seandunderdale]

ok, so no animating ramp inputs, or the phase / time of textures of noise textures, if you want motion blur? Is this likely to ever change do you think? Thats a lot of settings that cant be used for animation.

[hermit.crab]

ok, so no animating ramp inputs, or the phase / time of textures of noise textures, if you want motion blur? Is this likely to ever change do you think? Thats a lot of settings that cant be used for animation.

Yes, since motion blur is calculated based on the transforms of nodes (the change between one frame and another). Well, they can be animated, but they won't have motion blur. I'm not sure if it's possible - I'll ask the devs about it. Otherwise, in your case, you could animate the ring with a geometry that scales.

[seandunderdale]

The ring is mapped to folded cloth geometry, and that cloth turns from one material (cloth) to another (gold). The ramp is used as a mask to change materials, and also as a glowing edge. The issue is, or was, that none of this transition had motion blur. I could do the motion blur in Nuke, but I would have needed to set up the project workflow that way much earlier on. I'll upload the animation once Im allowed, to show how it was used, and what the issue is more clearly in this case.

[hermit.crab]

Just so you know, motion blur solely on textures was never supported, because it brings far too many additional calculations, which will run regardless of active motion blur or not. We might consider supporting only a particular texture, in which other texture maps might be plugged.

[seandunderdale]

Fair enough...it does sound like it would have more negatives than positives overall. Here is a link to the final animation. The ramp makes the glow edge, and the change from cloth to gold, so Im not sure how Id go about it getting rendered in motion blur. I didnt render linear 32bit either, so that would also need to be changed if I did the motion blur in Nuke. Let me know if you think of any other workarounds to do the same effect, but to get motion blur working.

[hermit.crab]

First of all - that's a great animation. Otherwise, I tried a few stuff, but to no avail. The only thing that might work is to somehow have a geometry that follows the material switch edge.

[seandunderdale]

Im also having other issues with animating the colour in ramps. If I render a single frame, I get what Im looking for. But often when Ive animated a colour input on a ramp, from black to white for example, when I render a sequence, the keyframes get ignored, and I dont see the output Im expecting. Its very frustrating to test render single frames in IPR, and fine tune animations, only to have very simple things like an animated value in a ramp get totally ignored during a long rendered sequence.

This issue has come up on another project, but I had it on the cupcake job posted above. I had to go back and re-render frames a lot manually to get animated ramps to even appear as animated.

[seandunderdale]

And to add....when I do get it to render something, its often incorrect....Here is a render of whats meant to be a glow from a background city at night....One is subtle and looks correct in IPR, the same frame rendered as a sequence looks totally blown out and wrong, ignoring all the ramp setup and keyframes. This is just a curved plane behind my scene, with self illumination on in a vray material. A ramp in the opacity slot to control the falloff. Very simple.

Now, I dont know if its a Vray issue, or if its a general issue with Maya and kepframing ramp inputs...but whenever I render this in IPR, its correct, whenever I render a sequence, it blows out. So time consuming to keep making workflow changes and keep testing between IPR and rendering a sequence.

I changed the workflow to not be animated, now its just a white to black ramp in a maya layered texture, with a black solid on top. Im animating the black solid to disappear over 40 frames, but the issue is still there. Looks fine in IPR, looks wrong with progressive render....but looks ok with bucket renderer. No idea whats going on then with progressive in this instance.

[hermit.crab]

And to add....when I do get it to render something, its often incorrect....Here is a render of whats meant to be a glow from a background city at night....One is subtle and looks correct in IPR, the same frame rendered as a sequence looks totally blown out and wrong, ignoring all the ramp setup and keyframes. This is just a curved plane behind my scene, with self illumination on in a vray material. A ramp in the opacity slot to control the falloff. Very simple.

Now, I dont know if its a Vray issue, or if its a general issue with Maya and kepframing ramp inputs...but whenever I render this in IPR, its correct, whenever I render a sequence, it blows out. So time consuming to keep making workflow changes and keep testing between IPR and rendering a sequence.

I changed the workflow to not be animated, now its just a white to black ramp in a maya layered texture, with a black solid on top. Im animating the black solid to disappear over 40 frames, but the issue is still there. Looks fine in IPR, looks wrong with progressive render....but looks ok with bucket renderer. No idea whats going on then with progressive in this instance.

Could you separate this issue's reproduction on a separate scene and attach it?

[seandunderdale]

Here is a link to a zip file. For me, when I render the scene in bucket or IPR, I get a dark gradient, as I expect...switch to progressive and it render SUPER bright. The scene has been heavily simplified, but the error is consistent.

Maya 2022.4
V-Ray 5 for Maya, update 2.2

(v5.20.02, revision 31334 from Mar 31 2022)

[hermit.crab]

Thanks for the provided scene. It seems there's an issue when rendering opacity-mapped objects with the progressive sampler and a render mask. I've logged the issue(internal bug-tracker id: VMAYA-12178 ) for dev investigation. As a workaround, you could either use the bucket sampler or render out a mask for the backplate to work with in post.

[seandunderdale]

Yeh, plenty of ways to get around this one, so wasn't a huge issue.