Where the bump gets strange
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Please upload a testscene that allows developers to reproduce the problem, and attach some images.
Please upload a testscene that allows developers to reproduce the problem, and attach some images.
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- Posts: 44
- Joined: Fri Apr 03, 2020 6:22 pm
Where the bump gets strange
Hi,
I tried to reacreate a bump, which was done in cycles. I needed a procedural noise, which is very small. I tried it with lux and it looked very strange. I invested some hours and that is the excerpt of it.
I used a procedural dot-texture. With normal scaling everything looks like it should.
Black shadow on the right, light on the left. Reminds me of the Playstation 1. But when I make the dots smaller by increasing the uv scale, the result of the bump looks strange. Here is a zoom of it This happens to triplanar mapped noise, too.
I think this behavior is the reason why I dont get my desired small bump, right? Is this a bug?
I tried to reacreate a bump, which was done in cycles. I needed a procedural noise, which is very small. I tried it with lux and it looked very strange. I invested some hours and that is the excerpt of it.
I used a procedural dot-texture. With normal scaling everything looks like it should.
Black shadow on the right, light on the left. Reminds me of the Playstation 1. But when I make the dots smaller by increasing the uv scale, the result of the bump looks strange. Here is a zoom of it This happens to triplanar mapped noise, too.
I think this behavior is the reason why I dont get my desired small bump, right? Is this a bug?
Re: Where the bump gets strange
It simply that the bump value a way too high. Currently it is 10cm aka 0.1. Somthing arround 0.001 to 0.01 should work.
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- Posts: 44
- Joined: Fri Apr 03, 2020 6:22 pm
Re: Where the bump gets strange
Ok, lets take the real world example.
This is what cycles looks. The red cube's width is 10cm If I try to achieve this result with lux, the result looks like this. It looks weired at the bottom of the image. Here is the shader tree, where you can see that the bump value is 0,0001 The map before the bump node looks like this If I decrease the scale to 1000, the result looks like this, which is somehow more realistic, but not the goal For me, it feels like that the bump gets broken, when the scale is too high. But if that is normal, how can I achieve the result of cycles?
This is what cycles looks. The red cube's width is 10cm If I try to achieve this result with lux, the result looks like this. It looks weired at the bottom of the image. Here is the shader tree, where you can see that the bump value is 0,0001 The map before the bump node looks like this If I decrease the scale to 1000, the result looks like this, which is somehow more realistic, but not the goal For me, it feels like that the bump gets broken, when the scale is too high. But if that is normal, how can I achieve the result of cycles?
Re: Where the bump gets strange
Is the object scaled?
Can you try to compare Cycles and Lux with exactly the same texture used as bump map (an image texture), to minimize other factors?
Can you try to compare Cycles and Lux with exactly the same texture used as bump map (an image texture), to minimize other factors?
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- Posts: 44
- Joined: Fri Apr 03, 2020 6:22 pm
Re: Where the bump gets strange
No, the object is not scaled.
Here is a video where I added a sphere.
I baked the bump map from the original shader to a 16k tif and applied it to the cycles and luxcore shader to drive the bump. In cycles everything behaves like expected. The baked map and the procedural map do a good bump.
If I take the baked map into the lux shader, it results in a good bump, too. But if i try to drive the bump by a procedural map, the bump doesn't appear. I tried to get the same greyscale "image" out of the baked and procedural map, but the bump results are very different. There are different strength in the bump-node. If I would use the strength of the baked-map node tree on the procedural-map tree I wouldn't see any effect at all.
https://streamable.com/bqg6cv
I'm curious about your answear.
Here is a video where I added a sphere.
I baked the bump map from the original shader to a 16k tif and applied it to the cycles and luxcore shader to drive the bump. In cycles everything behaves like expected. The baked map and the procedural map do a good bump.
If I take the baked map into the lux shader, it results in a good bump, too. But if i try to drive the bump by a procedural map, the bump doesn't appear. I tried to get the same greyscale "image" out of the baked and procedural map, but the bump results are very different. There are different strength in the bump-node. If I would use the strength of the baked-map node tree on the procedural-map tree I wouldn't see any effect at all.
https://streamable.com/bqg6cv
I'm curious about your answear.
Re: Where the bump gets strange
Then I guess the problem is somehow caused by the procedural texture you use in LuxCore.mischterlampe wrote: ↑Tue Nov 17, 2020 7:31 pm If I take the baked map into the lux shader, it results in a good bump, too. But if i try to drive the bump by a procedural map, the bump doesn't appear.
In the screenshot above you used fBM. Are you aware that this texture produces values in the range from -1 to 1? The negative values might be the cause of the problem, although I'm not sure about that. You could try to remap the values like so:
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- Joined: Fri Apr 03, 2020 6:22 pm
Re: Where the bump gets strange
Yes, I know that the fBM isnt the best thing to test out. This is why I took the blender cloud node in my latest example. Can you produce a small high frequent noise procedurally for the bump that looks like bump, even when you are 10cm away with the camera? I would happy to see how.
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- Posts: 44
- Joined: Fri Apr 03, 2020 6:22 pm
Re: Where the bump gets strange
I think I figured out something out.
How is process of using a procedural map when rendering? Is it baked to an image? If yes, is there a hard resultion limit?
For my feelings, the "procedural bump" looks okay as long as I have a resolution relation of 1to1. This means, if a virtual 2cm by 2cm cube is 2cm on the monitor, the bump looks ok. If I "zoom" in and the cube gets bigger on the screen, the procedural bump doesnt work anymore. Is it possible, that the procedural map is baked with 72dpi?
My problem now is, that we work in print (300dpi) and we need renderings up to 45 Megapixels.
Here are the image, which led mit to this conclusion.
16k map 2cm cube is 2cm on the screen procedural cycles 16k map Now the close ups.
16k map close up where the 2cm cube is bigger than 2cm on the screen procedural cycles 16kmap
Is it possible to change the resolution of the procedural map?
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- Posts: 44
- Joined: Fri Apr 03, 2020 6:22 pm
Re: Where the bump gets strange
I get the same result of the procedural map, that flat look, when I take the 16k map and plug it into the triplanar bump node. What happens there?