Bump Strength Question Tweet

[Andreas_Resch]

So sharing blend files makes no sense here? OK. I'll check out how to export ORBX files and if I'm successful will upload another version. But this issue is very easy to recreate as well.

[Andreas_Resch]

Here's the exported ORBX version of the second bump test. Not sure if it works ...

http://www.argfx.at/upload/Octane_BumpTest_02_ORBX.zip

27.16 crashed when exporting ORBX while render preview is running. Seems OK when preview rendering is OFF.

[Andreas_Resch]

I did a bit more testing. Trying to get it to work via OSL shaders. But with them it's the same result.

But here is another thing that I found out. I did an even more extreme test. I put an object 100x the size next to the normal sized one and reduced the UV by 100 to match the map size. As you can see, in the downscaled version it looks as if the color channels are drifting apart. And that might lead to the blurry and harsher look of the bitmap. To make it better visible, I reduced the Power value of the downscaled version to 0.01 - otherwise the bump map would be too dramatic. Maybe this helps with getting closer to the solution of the problem.

I also tried it with Normal maps and there everything is fine.

[linograndiotoy]

That's what I came up with in realtion to the bump mapping issue.

I've modified your scene a little bit.

On the small box, the bump intensity is set to 3.

Consequently, since the other box is 10 times bigger, to get the exact same amount of bump I've set the bump intensity to 0.3 (3/10).

This makes the bump effect for the two material totally consistent:

Of course that may be an issue as we have very different sized objects and we need to use UVs to map them.

Bump intensity shouldn't depend on the object size. Let's see what can be done to solve this.

Octane_BumpTest_02_Lino.blend

(1.67 MiB) Downloaded 99 times

[Andreas_Resch]

I've already tried a variety of approaches by modifying strength, gamma, contrast etc. It looks like it could work, but it really doesn't. As you can see in my previous posts it's not just about strength but also about sharpness. If you try the same with a factor of 100x, the situation gets a bit clearer. I fear this will have to be solved on the engine level.

[linograndiotoy]

As I stated already in my previous comment, this is a real issue which needs to be solve. And yes, as i stated already in one of my previous comments , it needs to be soved in Octane Standalone.

[Andreas_Resch]

We agree then. And no need for the annoyed smiley. I'm just reporting those issues. Thanks.

[linograndiotoy]

That's not an "annoyed" emoticon, just an "embarassed" one since I'm repeating myself.

By the way, while I think the intensity bump is something that should be solved (Cycles does it well), different sized object sharing the same material setting will still be an issue.

It's a question of workflow. The real problem here is not the object size, but the relative UV size of the meshes. If we fix the distance, we're fixing one of two correlated workflow issues.

And the other one (finding the correct "transform" size for different sized mehses) will still need to be solved "manually" by the user.

That's why other projection methods (Triplanar above all!) are highly recommended in these kind of situations, unless UV's for all the meshes in the scene are "proportioned".

I've made a scene showing the 2 boxes sharing the exact same material, and the same bump effect. You can change size and intensity as much as you need, and still get a perfectly consistent result, thanks to the correct relative size of the UVs, which solves both issues at once.

Octane_BumpTest_03_correctUVs_Lino.blend

(1.68 MiB) Downloaded 104 times

[Andreas_Resch]

Yeah. This problem is related to UV maps. Other projections work fine. But I often use UV maps where I can't switch to other projections. And then I'm stuck with that problem. I'm sure I can come up with workaround that will sort of look fine, but in the end this is a thing that you don't want to have to think about constantly. AI'm not sure what you mean by taking care of the transform sizes. But I'm happy to set the dimensions in the shader manually - I already do. It's just that I want to be able to trust in the appearance of the bump map once that is done.

Sorry about the misunderstanding concerning the emoticon. I'm not exactly an expert on those.

[linograndiotoy]

Oh, no problem Andreas, I could have been clearer without even using that!

I appreciate your effort to help us to make Octane better!

I reported the issue to the Standalone team, let's see what we can do.

Thanks!