Skip to main content
G
georged98240393
Known Participant
September 13, 2019
Question

Alpha Channel Bug / glitch - C4D - AE

  • September 13, 2019
  • 2 replies
  • 1329 views

[Repost due to marked as spam] I have a sequence of PNG images that have been rendered from C4D with the alpha channel checked. I have then imported this in to AE to find that the alpha is not working correctly. It is clearly present when I scroll across the timeline on individual frames however it is not perhaps 'caching' the whole sequence.

 

I've imported the sequence in to PS and transparency / alpha works fine, so it's literally just AE where the problem is. I've also tried interpreting footage in AE and checking 'straight' as well as 'premultiplied'. I've tried rendering the sequence as a TIF - the issue still persists. I have checked in PS to see if the alpha channel is there in the channels window and it is. In the image below you can see what the alpha should look like versus the results achieved in AE. 

 

Some more details:

- The object has a thin film material applied

- The object is not transparent or semi transparent

- When importing a single PNG in to AE, the alpha is not recognised.

- The alpha works when viewing sequence in isolation but not in composition in AE.

    This topic has been closed for replies.

    2 replies

    Mylenium
    Mylenium
    Legend
    September 14, 2019

    Use another image format. 8bit PNGs use indexed colors with exactly one transparency level. You will need at least 24bit PNG or use TIFFs alltogether. Noine of that has anything to do with AE, it's a basic thing about image file formats.

     

    Mylenium

    G
    georged98240393Author
    Known Participant
    September 15, 2019
    Hi there thanks for the reply - I rendered the whole sequence in TIF before I tried with PNG and exactly the same issue occurs.
    Jose Panadero
    Community Expert
    Jose PanaderoCommunity Expert
    Community Expert
    September 16, 2019
    Could you share your Cinema 4D file with us to evaluate it?
    Jose Panadero
    Community Expert
    Jose PanaderoCommunity Expert
    Community Expert
    September 14, 2019

    I think the problem is that you are using Ambient Occlusion. And when using Ambient occlusion, you must check Evaluate Transparency option in the Ambient Occlusion options. Thin Film shader has some transparency. 

    Terms & ConditionsAccessibility statement
    Using the community Terms of use Privacy Cookie preferences Do not sell or share my personal information ad choicesAdChoices