Question regarding model behavior in GZDoom

[Janitor]

In the modeldefs lump, i have the following code:

Code: Select all

Model DualPistols
{
   Path "models/dual"
   Model 0 "tris.md2"
   Skin 0 "skin.pcx"
   Scale -1.0 1.0 1.0
   FrameIndex DUAL A 0 11
   //etc, etc, etc
}

I was under the assumption that there does not need to be a sprite counterpart for a model, and that one could simply create sprite names in the modeldef lump. I have found that I do indeed need a sprite with the correct nomenclature in the /sprites directory to make this work. What is even more odd is that when I simply add a sprite named "DUAL" to my /sprites folder, suddenly it works for all frames of the model? Is there any particular reason for this behavior? Why do I need a sprite counterpart to my model?

EDIT: For reference, this is why I want to know

[Enjay]

Personally, I just use built in sprites. They will never be seen because GZdoom will replace them with the model. So, I just define my actor using POSS or SPOS or whatever sprites that I know are already there and them map the model to the frames.