Thanks to Mark Flider for creating the Syzygy object viewing modules.

szgview lets you view supported 3D objects. To view a file, run:

szgview myfile.ext

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.