Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] I need help! => Topic started by: leo3d on 2023-04-07, 10:20:28

Title: Curvature to opacity
Post by: leo3d on 2023-04-07, 10:20:28
I can't get the curvature node to work as a black and white mask to drive the opacity, nothing is displayed
the wireframe node works but the problem is that there is no option to detriangulate

thanks for your feedback
Title: Re: Curvature to opacity
Post by: Beanzvision on 2023-04-07, 10:30:32
Hi, can you share an example of your setup?
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 10:32:37
it work with refraction but no opacity
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 10:35:20
in fact I want to make a wireframe style rendering with the curvature knob
 
Title: Re: Curvature to opacity
Post by: Beanzvision on 2023-04-07, 10:39:22
it work with refraction but no opacity
Really? ;)

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39798.0;attach=181665;image)
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 10:43:20
could you show me your shader preset

thx
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 10:54:30
with self illumination it work; strange
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 10:57:45
sample
Title: Re: Curvature to opacity
Post by: Beanzvision on 2023-04-07, 11:28:10
Do you have more info on the look you are trying to go for?

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39798.0;attach=181671;image)
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 12:58:00
https://www.dropbox.com/t/VPG3hn8hZcIPuHCd

Try with this model

I don't see triangulate edge ;)
Title: Re: Curvature to opacity
Post by: Beanzvision on 2023-04-07, 14:12:26
Here's the model with wire and opacity:

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39798.0;attach=181679;image)

Another option to render a wire frame is to select all the edges and use the ''edge to spline'' command in C4D, you can then use a Corona render spline tag and the result is as shown.

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39798.0;attach=181681;image)

Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 15:00:50
ok but I don't want to see the triangles.
what is your solution with shaders
I use RKT mesh to spline but the model is too big for an animation. I'm looking for a solution to make the shape wire appear without seeing the triangles. Because I can't detriangulate the model, too long
Title: Re: Curvature to opacity
Post by: Beanzvision on 2023-04-07, 15:20:41
Are you referring to these?
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 15:46:24
yess
all geometry are triangulate and i wish don't see on wire ;)
Title: Re: Curvature to opacity
Post by: Beanzvision on 2023-04-07, 16:00:42
They are there, but then so is every other edge and it becomes crowded/messy. ;)

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39798.0;attach=181685;image)
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 16:08:24
that's why I want to go through the curvature node because the wireframe node doesn't fit in this situation
Title: Re: Curvature to opacity
Post by: Beanzvision on 2023-04-07, 16:45:00
Sorry, I'm still a little confused what exactly you want. Only edges? Only triangles? Or both? Do you have any reference images of the style you are after?

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39798.0;attach=181687;image)
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-07, 17:41:35
I want the outline of the object

Title: Re: Curvature to opacity
Post by: bnji on 2023-04-08, 01:23:33
Hi there,
I believe that you'll still need to optimize the model.
Please consider that if your model has been imported from a 3rd party app/host software, it will be loaded into C4D as a triangulated mesh, which is normal.
Once in C4D, you need to optimize the model (cleaning the model a bit); you can use the "Optimize" command and then run the "Untriangulate" command and see if the resulting mesh is what you're looking for.
You can't magically expect to solve the issues that come with an imported model made in another software.
I think I understand the result you're looking for, but still, I'll suggest first cleaning/optimizing your model, then using a shader or maybe using the suggestion provided by Beanzvision will take you to the desired result.
Cheers ;)
Title: Re: Curvature to opacity
Post by: leo3d on 2023-04-08, 08:40:07
Thank you for your feedback.
But not having the hand and time to clean the model I was just looking for a solution with the shaders.
For me there is a problem with the Curvature node when it is connected to the transparency.

But I found the solution. I had to activate the self illumination

But when I want to remove the shadows with the composition tag it doesn't work anymore
Title: Re: Curvature to opacity
Post by: romullus on 2023-04-08, 10:08:57
It's just a guess, but i think the reason why the curvature shader seemingly don't work for you in opacity slot unless you turn on self-illum, might be because opaque (the white part) in your shader might be too weak to be noticeable. Try to play with ray directionality and/or colour spread and see if you can get better result. You may also want to plug Corona colour correct shader between curvature and material and increase brightness and contrast there.