Bump mapping makes objects look faceted

[mrhalaby]

Hi,

I recently had to re render an old shot that we had previously done with vray 3.2 (now we are on 3.30.04), and although nothing had changed in the scene, I noticed one of the characters now looks faceted.

vray 3.2


vray 3.30.04



After having a look at the object, I've found out it has to do with the material we are using for the bump. It only happens with this map, and only when bump values are high. The only solution I have found is setting the Turbosmooth value much higher than we'd usually need (4 or 5 instead of 2), so that there's enough geometry to remove the faceted effect.

I attach a simple scene with the map on a sphere, so you can see the problem. It seems to be gone as soon as I lower the bump values, but this wasn't an issue before. Maybe you can throw some light on this issue.

Thanks!!

[Morne]

Actually now that you mention it, I had the excact same problem few days ago. I had a sofa fabric with high bump. I didn't notice anything in low quality tests, but at highres the sofa seemed faceted (and I know the model is fine). So it looks like same thing

[Svetlozar Draganov]

Looks like a bug, we'll report it into our bug-tracking system and will let you know when it is fixed.

[Lupaz]

It happened the same to me with Corona.
I added a smooth modifier, Autosmooth checked, and that helped a little.
Also I reduced the amount of bump. Weird though.

[Dave_Wortley]

@Svetlozar - Any news?

I've seen 2 or 3 scenarios this week where we've got unusual facetting and this could be the reason....

Just even a sphere primitive with a bump map seemed to have this problem.

[hoch5]

Same problem here. The cushions at the backrest show strong facets. While the bag in the foreground left corner is displaced and shows no artifacts.

[hoch5]

Any news on this? It is really annoying especially on cloth like materials. I haven't had the time to roll up to 3.30.04 but there is nothing in the changelog about it so i guess not.

[Svetlozar Draganov]

We are sorry to inform you but the issue is not fixed yet, as a workaround you may reduce the bump strength this will resolve the issue or use the version 3.30.03 which works fine.

[Morne]

Any news on this Svetlozar?
I'm on 3.30.04 and can't go down to 03 and also can't reduce the bump amount.
If I either set the bitmap's blur to 0.1 (no matter bump value) or increase bump to 300, the bug shows up. I have a texture which needs a strong bump and displacement is not an option

[mrhalaby]

try adding a turbosmooth on it, with a rather high number of subdivs. That will create so much geometry that the faces won't be visible but it will of course be heavier to render.

[vlado]

Any news on this Svetlozar?

I have not had a chance to look into this yet. You can use the environment variable VRAY_OLD_BUMP_REFL=1 to revert to the old behavior.

Best regards,
Vlado

[Morne]

Looks like this goes deeper than just the bump.

You can also reproduce this WITHOUT bump.

Make a new material with black diffuse (0,0,0). Make the reflection white (255,255,255). Set RGlossiness 0.5 and untick Fresnel. Facet deluxe even in material preview (3.30.04)

[vlado]

No, that's a different issue and has always been like that.

Best regards,
Vlado

[Vizioen]

Looks like this goes deeper than just the bump.

You can also reproduce this WITHOUT bump.

Make a new material with black diffuse (0,0,0). Make the reflection white (255,255,255). Set RGlossiness 0.5 and untick Fresnel. Facet deluxe even in material preview (3.30.04)

Even with Fresnel ticked it's noticeable. But it's also only with Blinn & Ward, not with Phongh and GGX.

[eyepiz]

I have not had a chance to look into this yet. You can use the environment variable VRAY_OLD_BUMP_REFL=1 to revert to the old behavior.

Best regards,
Vlado

Were do you set the environment variable?