Advise regarding reflection in image compositing

hello everyone,
I have been trying to composite an image but without much sucess. I’m sure I’m missing something (terribly) obvious here but I’m clueless.
To make a long story short:
#1. I pull a matte in the compositor and combine it with a backgroud plate (see attachment). The shot was taken during the day and i’d like to make it look like it was shot at night. The moon is not very realistic but that is the least of my concerns for now.
#2. I use a plane in the model to cover the sea surface so that the light which the moon supposedly casts is reflected in the plane (see attachment).
#3. My problem is that the rendered image is far from what I would consider acceptable: the light of the moon is not reflected in the water as it should be (see attached image). Leaving the bits per channel issue aside, I’m confident that I can achieve a better result with GIMP.
#4. If I choose ‘‘Tangent’’ In the material/shaders menu --which according to the preview is exactly what I’m looking for – the plane is rendered in white which I find hard to comprehend.

Any tips or suggestions would be welcome.


you could do this better in GIMP, photoshop, cinepaint, krita, etc.


I’m almost certain you don’t want to use tangent shading, unless you want the sea to look like brushed metal.

How do you want to reflect the moonlight? It looks like you’re trying to use specular reflections, instead of true reflections. This is fine - just make sure your sea material has a high specular value. You might need to move the light simulating the moon around until it is reflecting correctly. I’ve attached a crude example file.


moon.blend (199 KB)

thanks for the suggestions. Have tried Cinepaint but it crashes heavily in Kubuntu 9.04. I remember trying an older version (for 8.04 maybe) which was stable. Photoshop I don’t use as it’s not a FOSS app. Krita looks promising and I will give it a go sometime soon (I hope). I use GIMP exclusively and I attach a composition made with GIMP (using a different shot though)

I’m basically using Blender for video editing and compositing so I’m very familiar with the VSE and the compositor, the modelling part is kinda new to me. This was a first attempt to use a scene in the compositor. Your ‘‘crude’’ example appears to be exactly what I’m looking for! Thanx a lot for the blend file and the explanations! :slight_smile: