How to get rid of the black background.
- Add a floor, some ground plane
and
- Change camera background color
- Camera → Environment → Background Color
or
- Put a large sphere around your scene
- Create → NURBS Primitives → Sphere
- Has perfect UV mapping by default
- Put a Surface Material shader on it
- Black Sphere in render shelf
- Out Color → Create texture
- Ramp
- If it turns our vertical in stead of horizontal: switch type from V Ramp to U Ramp
- File Texture
- With new texture placement
- Rotate in texture placement node if sky / background is on its side
- If you are using directional lights with shadows, this sphere will block them
- Turn off cast shadows in the shape node of the sphere (sphere1shape) under Render Stats