VRayLayeredTex Blend mode not working with multiply style blends

[ricoholmes]

VrayLayeredTex

Multiply, Darken, Linear burn don't work as blend modes. Multiply should NEVER be able to BRIGHTEN the underlying layer.

EG: Layer 0 = Grey
Layer 1 = WHITE (ie should never have any effect on multiply style blends)

Layer 1 set to multiply.. result should be Grey. It's white.
Layer 1 set to Darken.. result should be Grey. It's white.
Layer 1 set to Linear burn.. result should be Grey. It's white.


Win10
Maya 2020
Vray Next for 2020
build 29789

[nikolay.kusht]

I cannot reproduce the same results here. Could you send us an example scene so I could look into this? Also, I would recommend installing and using the latest official V-Ray Next for Maya release(21 January 2020).

[SonyBoy]

Worth noting that the layered texture works from bottom up, not top down. I think there was some talk a while ago of making the direction of operations more obvious in the UI, as well as the addition of some things like being able to name each layer, but so far nothing seems to have changed. That said, unless I'm missing something about the functionality of the layered texture, the OP is right. I'm on Mac OS using Maya 2018 and an old build of Vray but getting the same white result with the three scenarios.

[ricoholmes]

Just to make things more confusing - visually it works from the top down, not bottom up..
Numerically it's consistent, with zero ( at the top in the UI ) at the bottom. 1,2,3 etc are then stacked on top, but below in the UI.


Either way, multiplying a white texture on top of a dark lower texture is giving white.

[nikolay.kusht]

From my tests, the blending modes work as expected. You could check our documentation to make sure that you take into account that adding a new layer, is placed on the bottom of the stack and it is considered the foreground (FG). The result of all layers above it is considered the background (BG). Layers are applied from the top to the bottom.

https://docs.chaosgroup.com/display/...VRayLayeredTex

[SonyBoy]

Well, considering multiple users are reporting this experience, it seems that if it's not a bug per se it's a usability issue. The UI for the layered texture as it is at the moment remains quite confusing. Is there some reason the UI can't be designed such that new layers are added at the top? This is clearly more intuitive.

[yolov]

Well, considering multiple users are reporting this experience, it seems that if it's not a bug per se it's a usability issue. The UI for the layered texture as it is at the moment remains quite confusing. Is there some reason the UI can't be designed such that new layers are added at the top? This is clearly more intuitive.

The order in which layers are stacked (bottom being the foreground and top being the background) is the same in vrayBlendMtl. If it makes more sense to change the order - we'll definitely consider it, but then we'll have different logic in different nodes.

[SonyBoy]

The blend material very clearly has a BASE slot, with all the other layers going into a separate part of the UI. Somehow this seems to be easier to understand than the layered material UI currently is, although since we're on the topic it wouldn't hurt to switch them both around so that the bottom element appears below all others. Even simply marking "Base Layer" or some such in the layered texture would help. Part of the issue is also that the layered texture features all those compositing modes and when things are upside down for some reason (personally speaking anyway) this makes it more difficult to figure out what needs to add, multiply etc. The blend material only currently has additive mode so this isn't an issue.

[yolov]

That's true, the blend material has a base. The problem with the layered texture is that you can move _any_ layer around, so even if we named one 'base' you can still change its place.
We'll see if it makes sense to allow changing the order in which layers are stacked or if you have other ideas - please share

As for blending modes - I agree, there's probably too many of them. If there's any modes you feel are never used, or confusing - we can remove them. Some of them are not easy to 'name' in a way that hints what the operation is, because the underlying formula is more complex than a simple multiplication or addition. They are very similar to what Photoshop offers or Nuke with the merge mode. Will it help if there was some in-line help or tooltips?