Render transparency material have a white background

Started by raphael, September 17, 2018, 01:08:44 AM

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raphael

Hi here,

I try to make a render of a machine with transparent doors. When I do my render I include transparency and used PSD or PNG format. And nothing work it's always white behind my machine.

You can see my render here when I put a black background afterward on my render:

But when I put another color background in keyshot no pb the transparency follow:

So I really dont know where the problem come from. Look like my transparency follow my bg.

Please help


DriesV

Hi Raphael,

What material are you using for the transparent doors?
When you want transparent materials to affect image transparency, then you should use 'Glass'. Materials like 'Glass (Solid)', 'Dielectric' or 'Gem' do not have transparency in rendered images. This is because they have more accurate color density and refractions, which would not look correct when put on a different background.

Dries

raphael

Quote from: DriesV on September 17, 2018, 01:38:26 AM
Hi Raphael,

What material are you using for the transparent doors?
When you want transparent materials to affect image transparency, then you should use 'Glass'. Materials like 'Glass (Solid)', 'Dielectric' or 'Gem' do not have transparency in rendered images. This is because they have more accurate color density and refractions, which would not look correct when put on a different background.

Dries

Hi Dries

Actually I use a custom material based on: Clear Shiny plastic, because I want my material to look like transparent polycarbonate.

DriesV

Yes, 'Plastic (Transparent)' also behaves this way.
If you want transparent materials to affect alpha in rendered images, then the 'Glass' material type is really the only option.

Dries

raphael

Quote from: DriesV on September 17, 2018, 04:15:33 AM
Yes, 'Plastic (Transparent)' also behaves this way.
If you want transparent materials to affect alpha in rendered images, then the 'Glass' material type is really the only option.

Dries

I try it with fast rendering it's work better with glass thanks! But I dont know if it's because I made a quick render but I can still see on the outline of the frame some yellow of the background..  And the shadow also is yellowish... (because I have a yellow background in keyshot).

raphael

#5

This is the result after 1hours render. the glass works better but still have some yellowish reflect and the shadow are really bad  because of my yellow background on keyshot :'(

DriesV

The semitransparent pixels (shadows and glass) will blend with whatever the background is in KeyShot. If you use a yellow color background, then the glass and shadows will have a yellow tint.
You should not have this issue when you use a white or black color background.

Dries

raphael

#7
Quote from: DriesV on September 18, 2018, 01:09:18 AM
The semitransparent pixels (shadows and glass) will blend with whatever the background is in KeyShot. If you use a yellow color background, then the glass and shadows will have a yellow tint.
You should not have this issue when you use a white or black color background.

Dries

Ok so I did the same render with a white background in keyshot and some shadow are ok but some are really white.


it's mean we can not really make a full tranparent render if there is shadow and transparent material?

If I have a white background in keyshot it's mean I will have to use my render in a white background afterward because it will look weird depending of the background?


DriesV

In your case, it will probably look better if you make the Environment Background black.
You will not see the shadows in the real-time view then, but they will still be rendered.

Dries