I have a scene where a space captain is looking out the window of his ship (outerspace). It is shot from outside the ship and I want the reflection of stars to be on the glass in front of him.
So here is the view

Camera > Reflection of stars on Window > Window > Captain

Kind of like looking at someone through the car window, you can see your reflection as you peer through it to the person inside

I have tried lowering the opacity on a layer of stars, but that doesn't seem to do it. Any other ideas?

Use Chromakey to key out the black background in the star field.
I found that the effect looks better if you select "Show mask only" in the chromakeyer.
Adjust the opacity on the stars if desired.

So are you saying that I just layer the star overtop and chroma out the black? That sounds good. I guess I am also looking for that reflection quality, in cartoons they just have to put those hash marks and it designates glass - I wish it were that easy with real life, lol.

What did you use to create the stars, David? Does that video/still have an alpha channel (or could you create it again with one?).

Do you actually have a window plane in the video of the spaceship or are you lookng to simulate one?

It is all done in a 3D program. I am using the avi as an animated texture. The 3D program has a background starfield creator that I am using. I just rendered out the stars as a single JPG.
The only thing I don't have right now is a plane in front of the animated texture. I am going to try that and put a transparency on the plane, that might help the simulation, but it will also cut down on the transparency through which to see the person on the other side of the glass. It is worth a try.

How about doing the whole thing in the 3d app, using your spaceman footage behind the transparent plane (window)?

What makes it look like a reflection?

1) It's only barely there. This is an alpha setting.
2) It's out of focus because the lens is focused on the captain (blur).
3) If the scene moves, the reflection doesn't move like everything else. If the scene doesn't move, make the reflection move (he's on a starship, right?).
4) There are other things in the glass, like what is probably a pretty heavy-duty bulkhead to hold in all of that air-pressure and fight off, well, space weapons. You can just use things like the gradient generator to generate curves, hard lines, alpha blends for highlight glints at window curvature (think about refraction, and use a curved window look against the ceiling, along with a distortion plug or a displacement plug 2-to-1).


These are roughly in the order that I would bother to do them. 2 and 3 could be swapped, but they both are cheap, easy, and effective.

Please don't do this whole thing in 3D. If you can't fake it in Vegas, you probably wouldn't think to turn on depth-of-field in your 3D renderer.

Please don't do this whole thing in 3D. If you can't fake it in Vegas, you probably wouldn't think to turn on depth-of-field in your 3D renderer.

But now he's been told to turn on DoF in his renderer, are there any other reasons he shouldn't do the whole thing in a 3d app?

While I agree totally with your great suggestions, it seems that if everything else that exists in this project has been built in a 3d app already then a) you'd think he knows a bit about 3d design already and b) surely it would be easier to just introduce a window in the 3d app with a transparent material that reflects the stars. That would certainly make the introduction of motion into the shot a lot easier than doing it in Vegas?