Author Topic: Triplanar mapping and displacement  (Read 1047 times)

2022-10-26, 14:25:19

RecentSpacesSam

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Hey all,

We were recently having some trouble with the triplanar mapping on displacement not matching the mapping on the rest of the channels and I discovered this thread https://forum.corona-renderer.com/index.php?topic=19726.15
The summary being "the mismatch is intended".

Would it be possible to add a checkbox/radiobutton onto the CoronaPhysicalMtl to allow the user to decide the order of operations between Displacement and Triplanar.
I completely understand the devs reasoning that displacement should be mapped prior the other channels but as an artist, there are use cases where we would like them all to by synced up together.

Cheers

2022-10-26, 14:32:23
Reply #1

PROH

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Tanks for bringing this up again,  and + 1000 for your suggestion.

2022-11-02, 13:55:41
Reply #2

philipbonum

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I didn't even know this was an issue, and would like this option as well, or at least a warning when putting it into displacement?  Would be awesome to have the ability if it is an easy fix :)

2022-11-03, 14:39:12
Reply #3

maru

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This was discussed many times and the only information we are missing is:
When exactly is this useful? Do you have some specific example/scenario where you would like to use this?

OTOH, V-Ray has this option ("use displaced surface"): https://docs.chaos.com/display/VMAX/VRayTriplanarTex
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2022-11-03, 15:38:11
Reply #4

romullus

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This was discussed many times and the only information we are missing is:
When exactly is this useful? Do you have some specific example/scenario where you would like to use this?

That is exactly what i'm constantly asking myself - "where is current behaviour useful?" :] I don't think i ever used triplanar in conjunction with displacement, because of that limitation. Personally for me, current implementation makes very little sense.
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2022-11-03, 16:03:43
Reply #5

Juraj

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I remember that the use case mentioned by Maru years ago was displaced terrain on which it makes sense to project afterwards. But even that scenario doesn't really fit well in my head since such terrains are displaced as baked-in from large-scale but not detailed height-map and tiled micro-displacement is used afterwards for further detail.

It really makes sense imho for 95perc. to make it opposite, and always align displacement with rest of textures in triplanar projection. Textures come in sets and displacement is almost always part of the whole PBR set and should match.

The Vray option is really nice ! Solves the problem completely.
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2022-11-03, 16:08:09
Reply #6

maru

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That is exactly what i'm constantly asking myself - "where is current behaviour useful?" :] I don't think i ever used triplanar in conjunction with displacement, because of that limitation. Personally for me, current implementation makes very little sense.


I remember that the use case mentioned by Maru years ago was displaced terrain on which it makes sense to project afterwards. But even that scenario doesn't really fit well in my head since such terrains are displaced as baked-in from large-scale but not detailed height-map and tiled micro-displacement is used afterwards for further detail.

It really makes sense imho for 95perc. to make it opposite, and always align displacement with rest of textures in triplanar projection. Textures come in sets and displacement is almost always part of the whole PBR set and should match.

The Vray option is really nice ! Solves the problem completely.


Guys, I am not sure if you are trolling me or not, but I am not asking where the current solution does not make sense, but where the new solution would make sense. Do you have some specific examples of using triplanar + displacement where you would like to see this new behavior?

Some of the previous examples show things like bricks or tiles. While the result looks incorrect indeed, I do not see any reason why a brick texture would use triplanar mapping instead of the regular UVW mapping.

I would just like to see some practical examples where using the new method would help.
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2022-11-03, 16:22:41
Reply #7

PROH

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Maru@ - I don't think anybody are trolling you. It just doesn't make sense to ask the obvious. Read the comment again, and you'll get the answer. Personally I need this every time I use triplannar with a material that uses displacement. I've NEVER needed the current behavior.

Regards

2022-11-03, 16:25:36
Reply #8

maru

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Maru@ - I don't think anybody are trolling you. It just doesn't make sense to ask the obvious. Read the comment again, and you'll get the answer. Personally I need this every time I use triplannar with a material that uses displacement. I've NEVER needed the current behavior.

Regards

Can you share 1-3 examples of such setup? What kind of real-life object and material is it?
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2022-11-03, 16:38:42
Reply #9

PROH

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ALL materials that I would use with triplanar.

For example ground materials as dirt with small stones on curved terrains where planar or box-mapping will give unwanted results.
Or when importing lots of objects without propper mapping, where triplanar gives a useable result in a short time.
Or with organic shaped objects without proper UVW.

I can't honestly imagine one single case where the current behavior is wanted. To me this is a pure theoretical solution.

2022-11-03, 16:41:02
Reply #10

maru

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For example ground materials as dirt with small stones on curved terrains where planar or box-mapping will give unwanted results.

We have one specific example so far, thanks!

We also have my example where we are displacing some curved terrain and applying grass to it, where the current order of operations makes more sense.

So the current score is 1:1.

Can anyone else make it at least 2:1 for the new behavior? :)
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2022-11-03, 16:50:31
Reply #11

PROH

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I don't think your example is used as often as ALL other usecases together. And your result could be done in other ways (f.x. by baking the displacement into the mesh), whereas the suggested behavior can't.

2022-11-03, 16:52:11
Reply #12

maru

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I don't think your example is used as often as ALL other usecases

Such as? :)
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2022-11-03, 16:53:54
Reply #13

PROH

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ALL other usecases!

2022-11-03, 16:54:26
Reply #14

PROH

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Are you trolling me?