Light only passes through static mesh when selected

Development Rendering
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1

Hi,

I just started working with UE4 and this issue has been bothering me for a couple of nights now. There are two questions regarding this problem on Unreal AnswerHub, but none of them offers a solution.
Basically, I have a static mesh of a window and it has three elements, so I can apply three different materials to it (for the glass, panel, etc). However, light doesn’t seem to be able to pass through the glass material unless the object is selected or the other two elements are set to glass as well.
Let me illustrate with a picture:

80801-1.jpg
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Here, the top window only has a different material on the handles, but the whole window is casting a shadow on the wall. The middle window has glass on all of its elements and the bottom window is what I want for my project, but as you can see it too is casting a full shadow on the wall. However, if I select the bottom window I get my desired outcome:

80802-2.jpg
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P.S. Lighting is built on production quality and I’m using UE4.10

Thanks in advance.

2

Hi AshkanPM,

This is a known issue with 4.10 with multiple material elements with a single mesh. This has been resolved with 4.11 and you can test this with the latest 4.11 preview 6 that is available on the Epic Games Launcher, or GitHub source build.

If you need to stick with 4.10 you can separate the mesh so that the glass is its own object. This should only apply to any translucent materials applied to meshes with more than 1 material element.

I hope this helps.

Tim