Rock Surface Study

Started by j meyer, June 29, 2020, 01:15:33 pm

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j meyer

Thanks.


Ulco - Thought about it again and it might be logic when you are adding some
more geometry to your model, but in case you just import a model again without
having done some modifying in another software and saved it with that, it would
be really strange. If you saved it with another software inbetween it could be a
different obj writing that can't be read by PR.
Just a thought that came up.

zaxxon

Thanks for posting all of the explanations with the examples. I'm following your progress with some interest. :)  I really like the way this is going and I'm using 3DCoat to try to achieve some similar things. I'm curious how you are setting up the cavity maps in the TG shader tree? I've never had much luck with those in TG. I do like the cracks. Keep up the fine work!

WAS

Quote from: zaxxon on July 23, 2020, 01:07:53 pmI'm curious how you are setting up the cavity maps in the TG shader tree? I've never had much luck with those in TG. I do like the cracks. Keep up the fine work!

Cavity map are a form of AO, so I believe in TG we'd want to multiply with a lower value you'd typically use for an AO map. Maybe add multiplied colour?

Dune

Thanks Jochen. I will have to check what really happens and may make some screenshots, but the vertices looked 'harder' after reimporting a saved obj, without changing the sculpt. Just adding stuff to it in PR.
If I make a crevices/AO mask in ZB, I always check how soft/grey it is in Photoshop (not completely black, but a nice gradient), and multiply colors in TG, or add an empty surface layer, mask it inversely and use a color adjust as child for manual gradation of the cracks/cavities.

j meyer

Ulco - when you add some stuff in PR (more separate geometry parts) it would
be something new and would have to be recalculated in case you added it to
the object, because it would be a new part of the previously model, I guess.

zaxxon - Thanks Doug. And now for your question.
If it the cavity-map was the only map to be combined with the color-map (image)
or the color done by PFs I would of course multiply it as usual (with a multiply colour
node). In this case there is - as you most likely have noticed - an AO-map and an
additional cavity-map. So this time I combined them a bit differently.

Color+maps.jpg

The transform input shader is set to 'Use world space' so that the PFs are applied correctly
over the the UVed Model.
The AO- map and the cavity-map are combined with a merge shader in the default mode.
Which means the merge mode - merge colour is checked and remains set to mix(normal).
With the mix control you can balance the two maps, either have them equal or one stronger
then the other.
It is done like this, because multiplying both maps leads to a somewhat darker result and
that is not what I wanted.
Have a look.

With the merge shader  cavi+ao-mixed.jpg

With a multiply colour   cavi+ao-multiplied.jpg

The same on the colored model.

cavi+ao-mixed+pf.jpg   cavi+ao-multiplied+pf.jpg

And since I used rather grayish (no black) maps it was much closer to what I was after.

The whole shader tree - without the greenish stuff - looks like this btw..

c-Whole Shader.jpg

Hope that this answers your question. Keep on more questions in case my answer didn't
answer enough.

WAS

Quote from: j meyer on July 24, 2020, 01:02:03 pmUlco - when you add some stuff in PR (more separate geometry parts) it would
be something new and would have to be recalculated in case you added it to
the object, because it would be a new part of the previously model, I guess.

zaxxon - Thanks Doug. And now for your question.
If it the cavity-map was the only map to be combined with the color-map (image)
or the color done by PFs I would of course multiply it as usual (with a multiply colour
node). In this case there is - as you most likely have noticed - an AO-map and an
additional cavity-map. So this time I combined them a bit differently.

Color+maps.jpg

The transform input shader is set to 'Use world space' so that the PFs are applied correctly
over the the UVed Model.
The AO- map and the cavity-map are combined with a merge shader in the default mode.
Which means the merge mode - merge colour is checked and remains set to mix(normal).
With the mix control you can balance the two maps, either have them equal or one stronger
then the other.
It is done like this, because multiplying both maps leads to a somewhat darker result and
that is not what I wanted.
Have a look.

With the merge shader  cavi+ao-mixed.jpg

With a multiply colour  cavi+ao-multiplied.jpg

The same on the colored model.

cavi+ao-mixed+pf.jpg  cavi+ao-multiplied+pf.jpg

And since I used rather grayish (no black) maps it was much closer to what I was after.

The whole shader tree - without the greenish stuff - looks like this btw..

c-Whole Shader.jpg

Hope that this answers your question. Keep on more questions in case my answer didn't
answer enough.

The only issue I see with that is when games apply crevices, it seems only to by multiplying the crevices, where everything else is masked out. It never affects whites. You should be able to use the crevices as their own mask for their crevices effect. Additionally when the multiply crevices is plugged into a child of a surface and masks with invert mask, you have the coverage slider to play with intensity. Even going over 1.

zaxxon

Thank you for the detailed explanation. In some other apps the cavity map adds additional detail to the AO map for the deeper 'crevises', and I guess this is what you're doing here in a TG way. I'll give your set up a go. Thanks again!

Dune

You can use all sorts of additions to setups like this, like a bias or gain scalar to influence the gradients in AO/cavity maps, or change the RGB/grey values in the image map shader itself, or multiply colors/scalars from the image maps by constants for more or less impact, etc.

j meyer

Never tried bias or gain scalar with image maps, might be worth a try, thanks. :)

WAS

Quote from: Dune on July 25, 2020, 02:22:44 ambias or gain scalar to influence the gradients in AO/cavity maps, or change the RGB/grey values in the image map shader itself

This is what I gotta do with most shipped maps as they do tend to come with gray tones from generating rather than baking from 3d. And in apps like Materialize, I can't actually seem to find a exposure/gamma type setting to whiten what it generates when I try to make a new one, so end up going into photoshop after that, and it's tedious.

j meyer

Just in case someone is interested, you can see a few more views and ZB renders
on my blog now.
https://orkwarts.wordpress.com/blog/

luvsmuzik

This whole concept is great experimentation and conclusive results! Thanks! :)