Since version 2.0, AKI ClipConvertor application allows to embed video warping channel into the clip. Warping allows to combine clip graphics and video data coming from secondary video input during production. Effects like virtual screen can be realized with that.
Video warping overview
Warping Clip Creation
To create GTC clip containing warping channel, the artist creating the clip in a 3D rendering application must render two sets of images:
- primary clip RGBA .tga, .png, ...
- video warping .rla
Video warping images must contain following channels:
- alpha channel defines where the video input is visible inside the clip area
- UV channel defines how the video input rectangle is mapped into the clip area
Tips for using 3ds max To Create Warping Clip
Rendering RGBA frames
Preferred RGBA format is TGA that allows to disable premultiplied alpha.
To get correct shading of the video surface, material of the video surface should have following parameters:
- Ambient black
- Diffuse textured, all white texture
- Specular Level 0
- Rendering video warp frames
To get correct warp alpha channel, any objects occluding the video surface must have applied matte material. A receive shadows object property must be disabled. Objects that do not occlude video surface at any moment should be set non-renderable.
In order to get correct UV mapping on the output, an object within scene that will serve as video surface must have applied texture. UV mapping can be set up precisely using UVW Map modifier.
It is useful to adjust UV mapping to slightly extend the video surface (5% on each side). Doing this crops black border that often occurs in video signal.