Arrow Modeling Conventions

[Ishtvan]

While coding projectiles, I would like to write some code that pushes the arrow into the wall by a variable amount. The problem is, I need to figure out the vector to push along. I could just use the velocity, but the arrow is rotating a bit as it's fired, so the axis of the arrow is not aligned with the velocity variable.

 

It's more correct and looks better to have the arrow push in along the direction of its axis when it hits. To do this though, I need a reference direction on the arrow to make my axis direction vector. This depends on the specifics of how the arrow is modeled. Most importantly, which local axis does the arrow axis lie along in the model? I.e., what local direction is the "length of the arrow," x, y, or z? Also, it's important whether the fletching to tip line segment lies along +x or -x directions.

 

First of all, I don't have any modeling program myself; can someone open up the broadhead.lwo and tell me what axis the existing broadhead model is aligned on?

 

Second, either we'll have to be sure to either always use the same axis for the length of the arrow and hardcode it in, or I can add a key/value to define the axis in the def file, so we can correct it easily in the def file. I'm inclined to go with the latter, since it's easier to correct one text entry than re-model the arrow, but I still need to know which axis the current arrow lies along.

[Ishtvan]

Almost forgot, the origin MUST be at the tip of the arrow in order for this to work. The collision model for the arrow is based around the origin, and this is what stops the arrow in flight and tells it that it's collided. In order to stick arrows in by a variable amount, I need to know when the tip of the arrow hits, not when it's already halfway stuck in the wall.

 

I think BT made a corrected broadhead model with the origin at the very tip, but I don't think this ever made it to CVS. Is it on the ftp?

[oDDity]

The current model is on the Y axis, with the head pointing up, and the origin is at the center of the shaft.

I updated CVS with the tip moved to the origin.

[Ishtvan]

Okay, thanks a lot!