Alpha in EnvMap


I have an (real) animation of a lake. I want to Add an object with Blender which is reflected by the water. I am using a plane with EnvMap texture as water surface. When I set “Alpha” to 0 so I can see the real water, the reflection is also invisible.

Are there no Alpha-Channels in EnvMaps? How can i solve this problem?

The way to do this is turn the col slider (under the texture buttons) down the more you turn it down the more the underlying surface shows and the less your env map shows. Find a balance that you like and there you go.
In case I did’t make my self clear RE: col it’s on the right hand lower side of the screen on the materal window.

I am assuming that you are combining real video of a lake, and want to add a blender object into the scene, and are using a plane with an environment map to reflect that object, but you want to be able to see through the plane, and still see the reflection…

The method I would choose is to have the envmap on the plane modify both the color and the alpha.

press both the [Col] and [Alpha] buttons in the material buttons for the envMap texture channel.

The brighter the color in the env map, the stronger the alpha. The Var slider will allow you to control how much the envMap affects the alpha channel.

Oh, and I would suggest that you set the material color to black, alpha to 0, turn ztransp on (required), and use add instead of mix for the texture, but it doesn’t really matter.

hmm seems to work now. My plane has now two textures. One for the background and the other for the reflection wich is added.

Thanks for your ideas!