1
$\begingroup$

I have a scene where I'm using a HDRI image for the background (and have a separate sun inside). The HDRI doesn't contain only sky, but also a bit of the ground. The problem with placing objects in the environment is that they don't cast shadow to the ground (as the ground is part of the hdri).

I am thinking about making a material to put flatly on the ground that would be: a) generally transparent b) giving a grey tint to the places where the objects shadows would be

How would I set a material like this? Or is there maybe a better way to achieve the shadows?

Note: I don't care about it being fully photorealistic with the ground materials etc (as this is obviously impossible), but rather would like to have a rough shadow where it should be.

the object on the background

$\endgroup$
4
  • 1
    $\begingroup$ maybe you are looking for shadow catcher: youtube.com/watch?v=7OOCjR5s9EQ $\endgroup$
    – moonboots
    Aug 15 at 11:31
  • $\begingroup$ precisely! Feel free to promote your comment to an answer $\endgroup$
    – sygi
    Aug 15 at 11:45
  • 1
    $\begingroup$ sorry I thought you were using Eevee, actually in Cycles it's even easier, just enable the Shadow Catcher option $\endgroup$
    – moonboots
    Aug 15 at 11:58
  • $\begingroup$ Yeah, I found the option once I knew what to look for :) $\endgroup$
    – sygi
    Aug 15 at 12:51
1
$\begingroup$

In Cycles you can simply select your plane and enable the Shadow Catcher option in the Object panel:

enter image description here

In Eevee you can use the trick explained here by CG Top Tips, which consists on the following node setup:

  • Diffuse RGB > (Converter >) Shader to RGB > ColorRamp > (Factor) Mix Shader
  • Diffuse BSDF > (Shader) Diffuse BSDF
  • Transparent BSDF > (Shader) Diffuse BSDF
  • Mix Shader > Output

enter image description here

Don't forget to choose Blend Mode > Alpha Blend and Shadow Mode > Opaque in the material Settings.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.