Hoping someone here may be able to help. I'm new to Blender (and game development/3d modelling) and have been following some tutorials online to get me started. I am building a very basic FPS just to get started. I have a gun that shoots a cube object as a bullet, but when I shoot a different cube object that I added as a target, I have a number of issues. EDIT: The target cube is just set as a rigid body object. No other attributes as yet.

  1. The cube only moves when I hit one particular face of the cube with a bullet. Otherwise, it doesn't register a hit. It's like the bullet passes right through it unless I hit the particular face.

  2. When I hit the correct face, the cube flies way off the screen. I know this is controlled by the physics of each object but I can't find any explanations of it. It's like the box has no weight. If I increase the mass of it, walking against the cube is affected. The cube moves around slower/faster depending on the mass, but shooting it shows no change.

Could someone give a newbie some pointers?? Thanks so much guys.

btw I'm using Blender 2.6 but I reckon that's irrelevant really


1 Answer 1


A couple thoughts: How heavy is the bullet you are firing? How fast is the bullet moving?

Edit: I'll expand on why I ask these. If the objects are the same mass, when one collides with the other, most of the velocity of the bullet will be transferred to the box. (in my comment I said energy instead of velocity, but the result velocity of each object depends on the relative masses during their collision)

You might take a look here: http://en.wikipedia.org/wiki/Kinetic_energy

One more: On one of my projects, I noticed that an object, when moving too quickly, would fall into another. I fixed this by tweaking the physics step settings under the World tab.

  • \$\begingroup\$ I'm not sure. I haven't assigned a weight to the bullet or a speed so I'm assuming default values here. Do you know of a tutorial or anything I could look at? \$\endgroup\$
    – adohertyd
    Aug 24, 2012 at 11:55
  • \$\begingroup\$ Ok I see now that I have set the bullet as a static object so I can't adjust for mass etc. Changing it to a dynamic/rigid body leaves it having no effect on the object being hit. \$\endgroup\$
    – adohertyd
    Aug 24, 2012 at 12:13
  • \$\begingroup\$ I'm sorry I don't know of a basic tutorial. If you are using default values, the mass will be 1.0 for both objects. Since the masses are equal, most of the the energy will be transfered into the target when hit. en.wikipedia.org/wiki/Newton%27s_cradle \$\endgroup\$
    – Noah
    Aug 24, 2012 at 16:45

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