bow rig help 3ds max

#1

Hey guys,
I know this isn’t a character rig like the forum says but I was hoping somebody could help me with a bow I’m trying to rig in 3ds max. In the image below I made some bones and an IK solver but it does not bend realisticly like a bow. any ideas?

#2

That kind of rig should work fine, except that you’ll want the rig to conform to the bow more closely when in the bind pose. The trick is to feather the weights gradually when skinning the bow to the bones.

FWIW the bows in Skyrim had a similar bone count.

#3

But see how the top and bottom bones(not the string bones) have a bend in the opposite direction? if the bow was skinned to those bones it would bend to the bottom bones but when it gets to the top bones it would stop the bend and be more straight. Also, I can’t move the bones individually.only the IK solver. How can I rotate the bones individually?

#4

You really need to have the bones conform to the mesh. You won’t get proper deformation otherwise. Reconfigure your rig so that the top and bottom bones align correctly to your mesh and so that your string bones also align to your mesh.

An IK Solver may not be the best bet for this, especially if you want individual control of the bones. You may want to use something like the Reaction Manager to rotate the bones a certain amount based on a helper position. Script Controllers or parameter wiring are also options.

#5

Ok I’ll work with the bones to conform them better.Right now I’m having a problem with the bones entirely though.the bone for the string won’t move at all. How would i fix this?

#6

You make the arrows ;)… as you can see it’s not that simple… and it is… the core idea is to bend a spline with the bend modifier, make another spline follow it with path constraint (WSM), path constraint few points to the second spline (at equal distances/percent), link everything to root point, orientation constraint all points to root, create several stretchy bones, link their drivers to path constrained points, create two more splines, one for the bow’s string, second to guide “pull point”, path constrain the “pull point” to its guide, connect “pull point” percentage along path to bend modifier in the first spline via reaction manager, skin the string’s vertices to top, bottom and pull point…
Try to “back engineer” this rig, there are probably more solutions but this was pretty fast one, it took me about an hour and a half… you will probably need more stretchy bones for your bow… and higher number of main splines vertices…

#7

This kind of thing can even be done using cloth wth high values…

#8

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