It seems that obj to psd conversion is not actually a file conversion, more like saving a view of the visualized model from singe point of view (slice). 3D objects (like those saved in .obj files) can also be saved or exported as pictures, such as the .psd files from Adobe Photoshop. What it does is create a picture of a static view of the model, or its slice.
Open OBJ file Open PSD fileA 3D CAD translation software