Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: cjwidd on 2021-06-08, 01:12:16

Title: UVWR - Additional Bump
Post by: cjwidd on 2021-06-08, 01:12:16
It seems like the Corona UVW Randomizer Texmap requires that greyscale bump maps passed into the Corona Normal Texmap as additional bump data, must also be passed into a Corona UVW Randomizer Texmap to generate correct tiling for the additional bump map.

I assumed that would not be necessary, but without also passing the greyscale bitmap into a UVWR, artifacts appear.

In this example, the 'WAVES' bitmap is assigned to the second UV channel and the 'NORMAL' bitmap is assigned to the first UV channel.

(https://i.imgur.com/fhuKrnP.jpg)



I feel like the UVWR is often more trouble than its worth - there seem to be a lot of 'gotchas' in terms of normal blending, integrating falloff maps, secondary UV channels, etc. Invariably I'm left with the appearance of a grid of tiles blended with some radius; the actual blending paradigm hides the seams, but produces other artifacts instead.
Title: Re: UVWR - Additional Bump
Post by: PROH on 2021-06-08, 01:46:47
Hi. Haven't noticed this. So I would like to ask: Does the same happen when both the Normal map and the Additional map uses the same UVW channel?
Title: Re: UVWR - Additional Bump
Post by: romullus on 2021-06-08, 16:15:09
I think it's expected that different mapping channels requires separate UVW randomizer nodes.
Title: Re: UVWR - Additional Bump
Post by: cjwidd on 2021-06-16, 01:44:47
I don't think UVWR is blending normal maps within a randomizer very elegantly, or maybe there is something I missed?

You can see the 'cross' pattern that is forming between the tiles - the material is only receiving a normal map.

This is a very high-frequency texture and it looks like the 'blending' areas are blurring the result, creating the cross shape around the tiles.

(https://i.imgur.com/lMC4yZH.jpg)

debug bitmap to illustrate randomization
(https://i.imgur.com/BqrGlye.jpg)

(https://i.imgur.com/MPz0rzW.jpg)

(https://i.imgur.com/3VTC7BC.jpg)
Title: Re: UVWR - Additional Bump
Post by: PROH on 2021-06-16, 02:47:25
I seldom use the blending default size (0,25). Typically I'll set it much lower, like 0,05. It depends on the texture.

Try to lower the blending size.

Hope it helps
Title: Re: UVWR - Additional Bump
Post by: cjwidd on 2021-06-16, 05:45:00
Lowering the blending amount does help, but does not resolve the issue. Unless there is something I'm missing, the blending method illustrated here is simply a limitation of the current implementation of UVWR.

(https://i.imgur.com/Ntbtewd.jpg)
Title: Re: UVWR - Additional Bump
Post by: romullus on 2021-06-16, 10:22:32
I don't get it. What do you expect from UVW randomizer? That it magically would make tiling and seams completely invisible? Substance has much more sophisticated tiling tools, but even them struggles with most textures. Corona's UVWR offers only basic blending, so you need to find the balance between blurring and obvious seams. It's not magic bullet.
Title: Re: UVWR - Additional Bump
Post by: cjwidd on 2021-06-16, 16:48:05
Right, I'm mostly providing feedback about usability - aspects that could be improved upon.