Render Alpha Image with Transparent Material shows through to Background

[Lazer_Safe]

I have been trying to render an alpha image of a product sample using inventor studio. The product has an LED illuminated e-stop on it and so I have configured the top material to be translucent with an illuminated material inside to produce the desired effect.

It works really well when rendering a standard image with background as you can see in the attached image. When I try to do the same thing as an alpha image it seems to see through the transparent material and all the material that is behind it. I have found this behavior is the same in both Inventor 17 and Inventor 21. The attached image AlphaErrorCapture shows the alpha pattern coming through on the translucent surface when rendering. The other two images show the final result of the alpha image and the standard renders.

Am I doing something wrong or is this a bug?

[Lazer_Safe]

I am replying to attach more examples from the other angle if it helps

[imajar]

I was able to reproduce the issue in Inventor 2019. Playing with settings made it a little worse or better, but this seems to me like a bug.

[andrewiv]

I can confirm that this happens in 2020.3 as well.  I agree that this is a bug.  @johnsonshiue can you confirm?

[johnsonshiue · Accepted solution]

Hi Folks,

Yes, I think this is a bug. I need to work with the project team and see what options we have.

Many thanks!

[Lazer_Safe]

Thanks for checking it out and confirming the behavior guys. We can fix it in post for now.

[rui_wang]

Hi paulg, 

Could you please help to share your assembly files with us for more investigation? Here is my email, rui.wang@autodesk.com

Thanks for your help. 

Thanks,

-Rui