Bump...

[iacdxb]

Hi,

I was trying bump (checkerboard) but I don't think its correct, it should be hard edges, not smooth.
I tried Displacement also.... but its also smooth.

Any other setting in bump channel...?

render view and bump material.


Thanks.

...

[TomG]

I'll admit to having no idea what those two images show :)

You mention using checkerboard in bump and displacement. Based on that, I added the C4D native Checkerboard surface to the bump channel of one CoronaMtl, and to the Displacement of another, and these are the quick and dirty results, bump on left, displace on right (used displacement World Size of 0.02 to give it fine detail and no artifacts).

Let me know more specifically what you were doing, if this was not what you meant.

Thanks!
   Tom

[iacdxb]

Hi TomG,

Thanks for reply.
That was render screen shot and used bum.
I am from VrayforC4D, A simple scene I did and then I tried with Corona to do it, I am not getting same bump results with Corona. Vray bump is sharp even a small tiny bumps but in Corona I am loosing the details.

May be some other method for good result.

See c4d file attached and render screen shots also.

Thanks.

...

p.s.
I am sorry if I am comparing this vray.

[iacdxb]

ahhhh... If use Denoise mode "None"... than stage bumps fine but cup edges not sharp.

I think... some Denoise  problem. I saw one c4d tutorial also, when he denoise sofa scene, all details gone.
I am not technical person, what algorithm or method used for denoising but seems some denoise problem.


Thanks.

[Eddoron]

I tried it myself but I don't know where your problem is.
The only thing that comes to my mind that would result in that noisy bump is that you have only let it run for one pass or so.
I used the c4d tiles shader(lines v-dir.) for my experiment but also tried a similar bitmap that also looked fine.
The only thing where artifacts occurred was with the displacement but that could easily be resolved by lowering the screen size setting and/or maybe unwrapping the uvs at the top&bottom.(though it was a pretty small object and not too close to the camera)
here's my take on it:

Ring on a cylinder on a plane with corona sun.
Left: Bump / Right: Displ.

[iacdxb]

Anyone tired my test scene file...? given above.

Thanks..

...

[Eddoron]

I tried your scene.
The problem is with the displacement screen size. The default value of 2 is too high for the fine contours you need.
It's also an adaptive approach and if the camera were closer, it would look fine.
The artifacts can be resolved by setting the displ. screen value to 0.4 or lower or if you want it to be static 0.001 cm will also do the job.
I'd also recommend to let it run for more than ten passes(I used 30 but less would already do it) and you'll see a crisp line.

The denoiser only makes sense when the image has gathered enough samples and finer details are already visible. The default value for such a scene would also be too high and you'll have to play around with the values until you're satisfied.

One more thing for the normal map that was in your folder.
If you want to use those, you first need a corona normal and inside of that the corona bitmap shader and set the color space to linear.
It also looks like the y value should be inverted for that map.

Hope I could help.

[mrittman]

I also tried your scene file but instead used the Tiles shader in the Displacement channel. Getting the same result. Very noisy edges. Seems like a bug with Corona to me. Should be getting crisp edges.

[mrittman]

I tried setting the Screen size of the Displacement settings to 0.4. Same result. It shouldn't need 30 passes. I still think this is a bug myself.

[Eddoron]

I've tried it again. Sure there are small artifacts but the area in the original view is very tiny, pixel wide and wouldn't be noticeable in a final render.
I used 16 passes. I had s.size 0.4 as max and a finer version with 0.2. In the close ups, I exaggerated the displacement to 0.15cm

1.original size 2
2. size 0.4

3. close up 0.4 300% zoom
3. close up 0.2 300% zoom

It should be cleaner but with final HQ settings, it wouldn't be noticeable. Maybe a little tweak on the AA settings could do the rest.
I don't know how the c4d shaders are handled. Some other renderers like Octane bake the shaders and you can choose a size.

edit: small mistake writing the numbers onto the pics 0.4, not 0.04.

[iacdxb]

Thanks guys for testing.

I did screen size 0.5, and set normal map with linear... now looks fine. Thanks Eddoron.

Whats the hi-quality render setting...?

Thanks.

...

[Eddoron]

Glad I could help.

There is no fixed HQ setting. This all depends on what you are going to create and tweak the values accordingly.

If you have a forest with lots of leaves for example, then a higher raydepth could be useful.

A scene that has a strong or many caustics could benefit from a higher value in the light sample multiplier and AA settings.

This is all very individual. Imagine it like tweaking the values in Vray (global subdivision multiplier, GI depth, dmc sampler etc. etc.)

Just learn what each value does, there aren't that many. That's the good thing of unbiased engines.
Then you can easily set up the rendering values for what you need. The documentation and the official YT tutorials are quite helpful.

[iacdxb]

thanks for update.

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[maru]

In this case I think the best solution would be to model the displacement, or use a modifier, like in this (3ds maxa) example here: https://forum.corona-renderer.com/index.php?topic=5967.0

[Rhodesy]

Bottom line is corona bump is terrible and has always been in C4D, I dont think its a problem in max otherwise we would have heard about it. I'm not a coder but there seems to be a stumbling block on this one. For me its coronas Achilles heal. Toms checkerboard example is a good one to show the poor bump performance. Perhaps the new bump converter shader coming in the next beta might help though? Quite often it helps to blur the map slightly in the shader - you get a more pronounced effect at the expense of sharpness.

I love corona but I have to admit the vray bump is undeniably better and much more reliable across its strength range and where using shaders or bitmaps.