What should be added to Substance 3D Designer
- Sampling Address Mode:
Currently only support warp.

This causes some additional node blocks to prevent some issues.
With bilinear sampling mode, coordinate which are extremely close to border causes some problem.
To perform mirror, clamp, border sampling mode, the user should build node graph.
Sample color, gray node should have the 3rd parameter, address mode. Warp for default value, and add mirror, clamp, border mode.
- Matrix
Native matrix support should be added. Since typical normal map is composed with vector 3, SD at least contains matrix 3, but actually not.
Current matrix2x2 is just a case of using vector 4. It requires matrix multiply node, not a simple multiply node.
3. FX Map – Quadrant
The current fxmap color system does not fit for adjust height offset. Only height scale can be adjusted. I suggest that the color variable for grayscale quadrant node should have a vector4 parameter which represents level in low, level in high, level out low, and level out high.
Put a more parameter to ignore black pixel. If 4 level parameters are added, some unwanted pixel pixels may cause problems, So a parameter to ignore black pixels should be added. Just like it of shape scatter.
