PNG Alpha Problems.

Hi there, I’m trying to add some icons/logos onto a model which I have. I have been using this very useful tutorial:

Although I have achieved a transparent background using PNG’s the quality upon rendering is not great at all. I have included a shot of how the render comes out, note the grey haze around the edging and the general dirty look of the supposed flat colour.

This one is the still I am using (although obviously on an alpha channel)

Thanks for any help you can give me on this, usually I would imagine this thing would be down to be oversizing the image or something? However it is quite small and the edges are clean… just with an odd grey field around them.

I’ve been playing around with this for a few more hours now and using .gif and not .png seems to have fixed the grey edges problem…

You must of course as well as pressing the RGBA button, press the Premul button. Both in the render buttons…

I’d be happy to help you out Steve. I’m having trouble seeing the full size version of your sample images though so I can’t see the gray haze ‘around the image’. The darker areas from what I can see may be caused by a ‘smoothed’ model with some surface normals facing in the wrong direction. If you’re wanting an alpha map (Transparency map) with either an off or on effect, make sure your map is strictly black & white. Creating one from the above image may give you a gray map which would end up with a semi - transparent part.
If you’re using a single plane with the image mapped to it, you may get a hazey / shiny area on the plane where your image is black. Turning the “Spec” value all the way down should eliminate this. If you desire a glossy image, you could also use a Black & white (or gray) map applied to the “Spec” value similar to your color map and alpha map.

If you’d like to send me a sample file I’d be happy to take a look at it for you. I should have time this weekend to respond to you.

Thanks for visiting my site.

Admin - Blender3D Club.