Collison mesh Export Trick in 3dsmax

 By Dnamro

Creating working exportable collision meshes can sometimes be troublesome and  it may be easier to use an existing object that has working collision mesh as a template.. 

This tutorial assumes you know how to create a collision mesh.  It's a shortcut and you should understand how to create a regular collision mesh before using this tutorial.   So, if you need to, check out this collision mesh tutorials first and then come back: 

Now that you understand how to create a collison mesh, your ready to learn a shortcut.  First load the standardmesh object in 3dsmax.   So for this example, we are going to be creating a collision mesh for a rocket.

Colexp2.png

Export it into a wavefront object using the 3dsmax export tool to use later for importing.

Colexp3.png

So the template object needs to be something simple like a crate.    Find a template object and load it.   Select one of the existing collision meshes:

Note:  You will need to import the standard mesh object, as you can't export without it

Selected crate.png

Now import the exported obj file from before.

type in materials.mtl in the materials Library field as below

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The imported object needs to be attached to the existing collision mesh.   Select the simplest collision mesh.   In this case I selected the Col2 or Col3 mesh.   The simpler the mesh the better.   

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Edit the select the crate and then select the attach tool on the right hand side

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... and the select the rocket to  complete the action.  The purpose is to give the imported object the same material properties as the existing object.   Improperly set up material properties can cause the collision meshes to fail to export at all.   This bypasses this problem because the material properties are copied to imported object.

Colexp11.png

Now change to face selection and select the crate and delete it.

Colexp12.png

Leaving just the rocket.    Optimize the rocket if needed.

Colexp13.png

Once the new collision mesh is ready, select the schematic tool.

Colimage015.jpg

delete the other collision meshes and clone this one to replace each of the others.   

Note:  The AImesh/col3 mesh is only needed for creating navmeshes. but there usually needs to be a Col0, Col1 and Col2.  Col 0 is for projectile collisions, 1 is for vehicle collisions and 2 is for Soldier collisions.

 Now you are ready to export.

The collision mesh can not be exported seperately, but must be exported as part of the whole object, which includes the standardmesh, collision mesh files and the textures.  For a high poly object, this can take a few minutes.    Check your exported folder and you should have the standardmesh and the collision mesh files.  Note that only one collision mesh file is created regardless of how many col0 - col 3 objects your created.   Now you can take this exported collision mesh file and transfer it into your object's mesh folder.   Note that the collision mesh goes in the objects server zip file while the standard mesh and textures go in the objects client zip file.   The server only needs  collision meshes while the players only need the standard mesh.

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