UP Studio 3 has a texture mapping tool that able to project an custom image onto the surface of a STL model. Here we provide a step by step tutorial showing how to do this.
1. Load a STL model
2. Load a custom image by right click on the model and choose "Image Texture"
3. Adjust the parameters of the projection and choose how much thickness to add to the model. Use the preview button to check if the projection is satisfactory.
4. Click ok to convert projection into a submodel, use "separate" mode for the submodel.