Transparent backgound

Mr Tee · 19 Jan 2011, 15:54

Hi! Im making a flythrough using Proper animation and smooth step.
Is it possible to render image sequnce with transperancy in the background, for layering in post?

Gaieus · 19 Jan 2011, 17:03

On a Mac, (I guess) it would be possible - it can render images with transparent background with native SU (though I am not sure about the animation).

If you used other software (like 3rd party renderers), it would be possible to render the alpha mask for the animation, too - then it is just a matter of a batch routine in an image editor.

Mr Tee · 20 Jan 2011, 10:30

Thank you for answer!
No Mac here !!

for this project i'm not using any 3rd party renderers.

Soo there is no alpha support for sketchup?

Can you get transparent background uisng styles?

TIG · 20 Jan 2011, 12:02

If you set your background to a specific color - say 'White' - and export all if the images as PNGs for the animation you can post process them in free tools like Gimp. There's a batch processor that might swap out that color as 'transparent' etc...
Remember you need to remove the sky/ground and have suitable shadow casting set in each scene tab...

I'm thinking of making a jar tool to do this - I already have 'gifxtractor(folderpath)' that takes a selected animated gif file and makes all frames as png files. I see something like 'pngwhite2transparent(folderpath)' where any png files in the given folder are copied into a subfolder called 'PNGwhite2transparent' and each is processed so any pure white pixels [255,255,255] become transparent... What do you think ?

Gaieus · 20 Jan 2011, 12:20

That would be neat, TIG.

Mr Tee · 20 Jan 2011, 13:32

Thanks for reply TIG!

The tool your talking about making sounds great, an easier to do!
Thanks for advice about process image tool like Gimp, do u know any other free app that could to that?

Chris Fullmer · 21 Jan 2011, 02:07

Mr. Tee, what are you using for post?

You could do the animation export. Then do like TIG suggests and put white background on, no sky or ground. Then set the default front and back faces to pupr black, and turn on the display style that shows only front and back face colors and turn off edges and shading. You should be able to get a perfect black and white render of the video. Many post processing apps should be able to use that as an alpha map (I think).

Chris