Voxelizer is the go-to software when it comes to multimateriality. Multi-extruder toolheads are natively supported, making it possible to harness the full potential of double, quarduple and mixing nozzles.
Drag and drop or right click to simply assign materials.
Assign different printing settings for different extruders, for example ABS for the left and PVA for the right.
Use image mapping, one of Voxelizer's exclusive features to map and print any image on your model. And if your model has a texture attached to it you can print it directly!
Create gradients with a dedicated tool.
Use voxel selection and manipulation to assign the material you want to whatever part of the model you desire. You can even paint!