Making a collision mesh for this model..

Discussion in 'Mapping Questions & Discussion' started by efciem, Jul 10, 2008.

  1. efciem

    efciem L69: Deviant Member

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    Hey,

    Its been ages since I had to make a collision mesh for a model,

    let alone one kinda complex like this pipe elbow joint im working on..

    Its a 90 degree Turn , joint for a large pipe that players will swim through.. So I need the collision mesh to surround the interior or the pipe as closely as possible..

    using 3dsmax, how do i do a collision model for this! ughh

    here's a pic
    [​IMG]


    any suggestions as to how to tackle this collision mesh?
     
  2. Hawk

    Hawk L7: Fancy Member

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    The big problem you're going to run into is that for imported objects, the collision model must be a completely convex shape, or made up of several completely convex shapes. That means the mesh can't have holes or even any indentations.

    You could potentially put enough convex meshes in there to approximate the curvature of the pipe, maybe making a sort of octagon of meshes whose clones follow the curvature, but it would mean having a lot of objects to worry about. I would imagine no fewer than 32 different meshes.

    Honestly, if it were me, I'd go the easy route and disable its collision in Hammer, and then just throw some clipping brushes around it to simulate the collision meshes you would have made.
     
  3. Shmitz

    aa Shmitz Old Hat

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    The tough part is that the model compiler maxes out at 22 objects in a collision hull, and if you want any approximation of curvature, you're not going to be able to get that in under 22. Hawk's suggestion is probably the easiest. Have no collision hull, and block it out in hammer using nodraw brushes (make them func_brush instead of func_detail, so that they don't interfere with the model's lighting).

    If you really do want to make the collision hulls though, you'll have to sacrifice the realism of the curvature. Open up props_gameplay/sewer_entrance01.mdl in the model viewer, go to the Physics tab, and check the "Highlight" option. You'll see that Valve used 6 parts for the horizontal section and 4 parts for the vertical section. The bend is a little funky, but it basically uses two wedge sections to curve upwards.
     
  4. efciem

    efciem L69: Deviant Member

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    Yup I have spent a while, trying different convex shapes to approximate the curve of the pipe in under 22 objects,

    messy indeed. Clip brushes are going to be the way to go for sure..

    there are only going to be 3 of these corners in my map, make it for one, copy it over for the other 2 n' i should be good.

    seems like the best way to me.

    onec again y'all are very helpful in pointing me in the right direction.

    mad respect for all of you.