Shadows from translucent elements

I want to see through trees for building renderings, but still want them to cast shadows. Am I trying to have my cake and eat it too?

By “renderings” do you mean images exported directly from SketchUp or are you using some rendering application?

directly from sketchup. I’m exporting some jpegs for use elsewhere.

Materials in SU need to be over 70% transparent to cast shadows. Try bumping it up a bit and see how it looks.


I see. So for straight out of SketchUp shadows, materials will cast shadows as long as Opacity is set to 70 or higher. Have you tried that?

I can think of some post-processing methods where you’d combine several different image exports from SketchUp that could work.

that worked, thanks. I did not know about the 70% threshold


A work around that is pretty easy to get trees faded more than 70% and still have shadows is to export an elevation of the tree you want. Then in photoshop or other app, fade it as much as you like. Then save as PNG and import into SU…explode image…trace around tree…delete extra space and make component. Then you have 40% opaque tree with shadows!


tree-fade.skp (70.0 KB)
Here’s my faded tree I made in about 3 mins.

If you have photoshop you can export elements such as trees on layers and gain some further control as to how they look.
This course has some good tips for that.

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I great way to create what you’re looking for is to use a little program from Render Plus Systems called RP tree maker. It’s free and provides you a really cool method that’s not only easy to work with but great fun as well. Basically you build your own tree. The output is a 2D Face Me image component with an alpha (transparent) background. The leave density is also controllable so you can easily decide how much you’d like to see through it plus a nice soft shadow is also cast.
You can find some examples I did if you search for 2 Nice Trees on 3D Warehouse.

Thanks for that tip, I tried it out and it works well to generate custom trees as face me components.
I had used renderplus many years ago but have since moved on. It’s still a bit DOS like and doesn’t seem to have improved its rendering capabilities much, but this standalone tree generator has a very comprehensive interface to customize a tree exactly as you might like it. While it may no be able to compete with Laubwerk or other 3D proxies it would certainly hold its own for any background trees.

Yeah, it’s pretty ■■■■ good for $0.00