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Transparant Titles rendered with transperant/masked background
Hey i recently rendered some titles in cinema 4D and i want to include a background video behind it, now what i’ve done is i rendered the titles with a green background to simulate a “greenscreen” and then keying it away in after effects, but due to hugh reslution (720p) no matter how i try to key it i end up still having green colors around the titles and when i try to remove them it damages the qualty of the render, now maybe i’m doing something wrong or maybe i’m using after effect’s standard plugins so maybe theres something better out there or maybe a tutorial you could point me to ? or maybe a more simple solution in cinema 4d ?
Thank you in advance ! -
7 Replies
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Hy there,
really simple: just render out the Alpha channel. Like that you got a perfect mask, no need for keying.
Another way would be to add an object buffer with a Compositing Tag. This would also give you the perfect mask. This is necessary if you have a Sky or something that would fill up your alpha.
Cheers,
André -
Can AVI renders hold alpha information ? :S or do i need to change something ? any tutorials on how to do this, i’m new sorry 😛
And thank you for the reply. -
Yes, it can have an alpha channel if not compressed (maybe some of the codecs too). So just tick “Save Alpha Channel” in the Render-Setting under Save. There you also have the format that you render out, in your case an AVI. So click the Options on the right and say “uncompressed”.
But I recommend not to go this way. Your AVI file will become huge. It is better to export for example as OpenEXR sequence with enabled ZIP compression. You get (if you choose so) 32-Bit per channel (more information as in your avi, 8 bit per channel) and you will get smaller size overall. OpenEXR can be handled by any decent compositing program. 32-Bit will give you more degrees of freedom with handling exposure in compositing.
Cheers,
André -
Well the first option sounds easier enough but don’t i need to configure it in terms of color ? like keying or he automaticly masking the background and it dosent work on colors. and my file is like 15 seconds long in 720p how much space would it take ? and i guess it won’t take longer to render because he still renders it frame by frame.
but i havent worked with OpenEXR and half of what you said was chinese for me 😛 so is it like a plugin or a seperate addon ? any tutorials on my matter that i can find anywhere ?
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Here is a tutorial on using object buffers to do what it sounds like you are trying to do:
Hope it helps.
Tim
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Tim Shetz
c4dtraining.com -
[Philip Makarevich] “Well the first option sounds easier enough but don’t i need to configure it in terms of color ? like keying or he automaticly masking the background and it dosent work on colors”
Yes, it is not based on colors. I guess you are used to work with compositing software.
If you work in 3D you have a big advantage: there is no need for keying. Because the renderer knows what pixels of an image belong to an object or not. So, the renderer can *include* this information into the image either with an alpha-channel or an object buffer.
[Philip Makarevich] “and my file is like 15 seconds long in 720p how much space would it take ?”
That is hard to say, depends on how much information each frame carries.
[Philip Makarevich] “but i havent worked with OpenEXR and half of what you said was chinese for me :P”
OpenEXR is just another file format for images like TIFF/TGA .. but it has superior capabilities, like ZIP compression. You can work with OpenEXR like with any other image file.
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Well i did the video render with the alpha enabled as you instructed, i found this the easier option 😛 and it takes around 1.2g which is not that bad anyway and i got tons of .tif files with the alpha channel on them now when i add the footage to after effects it’s still not transperant, how do i enable the alpha channel ? or am i doing something wrong again ?
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