Thanks to Mark Flider for creating the Syzygy object viewing modules.
szgview lets you view supported 3D objects. To view a file, run:
If your HTR and OBJ files match:
szgview myanim.htr mymesh.obj
The bar at top displays the current mode. Press 1 to translate the object by click-dragging the mouse. 2 rotates. 3 scales.
If the file has animation, a slider and frame number appears at bottom.