Gobos and PNG Issues

Hello, I'm having an issue with creating a "gobo" effect (as depicted in a previous post). I import a texture with a PNG (with alpha channel), yet no light shines through?

Thank you in advance,

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Permalink Reply by Tolstoy394 on March 11, 2013 at 12:09pm

Okay, I worked around this with a few steps:

1) Use the paint dropper to copy and paste the PNG transparent pattern on both sides of this surface as depicted above.

2) Right click on this transparent PNG and "make unique texture" (do this for both sides).

*I don't know why, but these steps worked and allowed the iRender nXt light to shine through as desired (to make that "gobo" effect).

Any inkling as to what is hindering these PNGs from acting as transparent surfaces?

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Permalink Reply by Rich Hart on March 12, 2013 at 8:22pm

Could you post a model here that we could test?

If you put an skp file in . .zip file, you can use the Upload Files button to attach it.

Thanks.

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Permalink Reply by Tolstoy394 on March 13, 2013 at 11:14am

Here is the version that simply needs the next step of "make unique texture" before the gobo works as desired.
Thanks again

Attachments:

TEST GOBO.zip, 75 KB

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Permalink Reply by Rich Hart on March 15, 2013 at 8:37am

It turns out that that image is a Greyscale png. Which we don't handle correctly for transparency.

When you "make unique texture", SketchUp changes it to an RGB Color type of png file which we process OK.

I opened the Greyscale png in Photoshop and saved it as an RGB Color png. Below is a view of SketchUp, and a rendering, with the original Greyscale png on a face on the left, and a face with the RGB Color png on the right.