how is it possible to apply roughness, in the water material, only in the highlighted part of the mesh? Thank you
You could do this by creating a black and white mask and using it as the factor of a mix shader to mix the water with the rough water.
- First add an image texture node.
- Click new to add a black image.
- Then plug this into the material output.
- Then go to the texture paint workspace.
- Paint the areas you want rough in white.
- Save this black and white image.
- Go back to the shading workspace.
- Add a mix shader
- Plug you black and white image into the fac input
- Plug you water material into the top shader input of the mix shader node
- Add another Principled BDSF shader and increase its roughness
- Plug this into the bottom shader input of the mix shader node
This is the result you'll get:
Of course, from here you can make the rough shader more interesting with colour/bump/etc but this is the basic setup!
If you're rendering in cycles then:
- Setting the roughness to 0
- The transmission to 1
- The colour to true white (by default it's slightly grey)
is really all you need to do to achieve physically accurate water. However, you could also add some displacement either in the material or as a modifier on your mesh.
For example using a noise texture in the material displacement: