Author Topic: UVWR - Additional Bump  (Read 779 times)

2021-06-08, 01:12:16

cjwidd

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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.





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.
« Last Edit: 2021-06-08, 01:25:50 by cjwidd »

2021-06-08, 01:46:47
Reply #1

PROH

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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?

2021-06-08, 16:15:09
Reply #2

romullus

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I think it's expected that different mapping channels requires separate UVW randomizer nodes.
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2021-06-16, 01:44:47
Reply #3

cjwidd

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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.



debug bitmap to illustrate randomization




« Last Edit: 2021-06-16, 02:22:57 by cjwidd »

2021-06-16, 02:47:25
Reply #4

PROH

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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

2021-06-16, 05:45:00
Reply #5

cjwidd

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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.


2021-06-16, 10:22:32
Reply #6

romullus

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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.
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2021-06-16, 16:48:05
Reply #7

cjwidd

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Right, I'm mostly providing feedback about usability - aspects that could be improved upon.