Vray: render shadows at invisible object

SketchUp
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#1

Hi all,

After a years long break, i started myself a new sketchup project: a cirrus airplane. If i render this airplane with Vray, using a hdri map, it doesn’t show the shadows at the hdri map.

If i render it with a face below it, the shadows do appear:

So basically, i am looking for a way to display the shadows at the hdri map. A possible way is to make the green face invisible, but the receiving shadows at this face not. But how to achieve this? If i make the green face invisible, the shadows also disapear …
Does somebody have a workaround or solution?

#2

Hi there. This is a tricky one and maybe other V-Ray users will know better but anyway.

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Here under the Environment tab you can see GI (skylight) and Reflection/Refraction (background). Basically, the shadow doesn’t appear on the grass field because that grass field is a part of your background HDRI. It’s not a “real” 3D object to receive shadows.

You most probably didn’t apply the same HDRI to background AND skylight, because in that case your sun shadows would look different.

There are some video tutorials on YouTube that teach how to combine the SketchUp sun with a V-Ray HDRI but they’re not the best ones.

#3

It sounds like you need to use a shadow catcher. Other packages have them; it appears that V-Ray has now got one in V2…

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#4

Thx Alan! after some tweaking it turns out great with the use of Wrapper Materials.