Scale a texture using an Opacity map

[GoTy]

Hi,

I am using C4D and Corona rendering since a long time,
there always something I wanted to figure out about how to scale a texture which uses an opacity mask.

Please find 2 screenshots of my scene, basically I want to apply a moss texture to the bottom of the mountain only.
Instead of selecting some polys, I'd like to use an opacity mask.

However, this works only if the material is applied at 100% scale to the object (Mountain).
But the Moss material is obviously way too big for that mountain.

As soon as I scale down the material scale on the object,
it also scales down the opacity mask so it creates a totally different effect.

Is there a way to keep the opacity mask at 100% and to scale down the Moss texture at the same time to achieve the desired effect ?
I hope my explanation are clear.. :)

This subject might have been discussed before,
in that case could you kindly indicate where ?

Otherwise, can you kindly let me know how to proceed ?
Thanks in advance !
Regards

[John_Do]

Hi,

You can scale the moss texture independently from the texture tag in several ways :
- by using a Corona Triplanar shader (though it changes the projection)
- by using a Corona Bitmap shader (so you can scale the texture without changing the projection)
- or by using a C4D Projection Shader (almost the same as the Texture Tag but at the shader level)

You can also modify the gradient scale using '3d - Linear' mode and the appropriate dimensions. Be mindful that the viewport preview is quite limited though.

[GoTy]

Hi John,

Thanks a lot for your super quick reply !!

I would like to try your recommendation, however I cannot find any shader like that in the corona shader list..  see attached.

I am on Cinema 4D, not 3DS Max..

I will experiment the gradient scale option first, thanks for that !

Best regards

[GoTy]

Found it !

Using 3D liner gradient on object more (not texture)..

The values should match with the object height..

Then it's possible to scale down the moss scale using the UVW,

But the opacity mask keep the same shape using this method.

Thanks again for your help !

[John_Do]

Hi John,

Thanks a lot for your super quick reply !!

I would like to try your recommendation, however I cannot find any shader like that in the corona shader list..  see attached.

I am on Cinema 4D, not 3DS Max..

I will experiment the gradient scale option first, thanks for that !

Best regards

Shaders are added inside a material, so you will not find them here but in the menu next to each texture channel :



Every shader is described in details in the docs.

[davetwo]

As you are in C4D - Id strongly suggest that you look at using cinemas built-in terrain shader.
It is made specifically for this purpose, and you can get some very nice results by blending based on altitude, slope angle etc (use it as the mask in a layer shader)

[GoTy]

Thank you very much for your help and advices !
greatly appreciated !!

[GoTy]

As you are in C4D - Id strongly suggest that you look at using cinemas built-in terrain shader.
It is made specifically for this purpose, and you can get some very nice results by blending based on altitude, slope angle etc (use it as the mask in a layer shader)

I've played a bit with the terrain mask shader, on a C4D classic material.. it works well, thanks..
 
However, since I'm working with Corona render, how does it work if I want to blend 2 corona materials (like moss and mountain rock) with their own spec (diff, roughness, displacement..) and use the terrain mask shader to blend both ?
I don't figure out how and where to apply the terrain mask shader in that case ?
since it requires a layering system.. I though the Corona Layered material could work, but it doesn't ..

Thanks for your help !

[John_Do]

It works here, what's your setup ?

[GoTy]

Sorry my setup wasn't correct, it does work.
Is the only way to scale down each material inside each shader scale (diff, rough, bump, disp..),
or is there a global scale setting somewhere?}
thanks !