[Tutorial] Simple rag doll in BGE

[hydra_skillz]

Start a new scene and go into wire frame mode. Add a plane and scale it up 5 units.

Building the man
Go into front view and select the cube and scale it down .5 units move it up .5 units (z axis) . Duplicate the cube and scale it down to .1 and move it to the side using ctrl so it is locked to the grid (we will use this later). Select our cube and press N to bring up the Transform Properties window and rename it to Right_Foot.

ss1.jpg (171.88 KiB) Viewed 11032 times

Now go to the logic panel (F4) and change it from static to rigid body, set the radius to .6, and bounds to box. Now duplicate Right_Foot and move it over 1.2 units (x axis).

ss2.jpg (179.72 KiB) Viewed 11034 times

Select both cubes, duplicate them, and move them up 1.2 units (z axis). Add a cube and scale it 1.1 units (x axis) and 1.2 units (z axis) and move it .6 units (x axis) and 3.6 units (z axis). In the logic panel, make it rigid body, radius of 1.2 and box bounds.

ss4.jpg (181.19 KiB) Viewed 11031 times

Now duplicate one of the leg cubes (doesn't matter which one) and move it to [-1.2, 0, 4.3] (these are x, y, z world coordinates, you can enter these numbers in the Transform Properties window). Duplicate it again and move it to [-2.4, 0, 4.3], then select both arm pieces, duplicate them, and move them over 4.8 units (x axis). Duplicate one more cube and move it to [.6, 0 , 5.5]. Rename the cubes like in the picture.

ss5.jpg (199.41 KiB) Viewed 11031 times

Adding Joints
Select the tiny cube we made in part 1. Go to the logic panel and make it rigid body, .1 radius, and sphere bounds. Using ctrl for grid lock, duplicate and move the cube to these positions.

ss6.jpg (262.38 KiB) Viewed 11032 times

Give them sensible names like Right_Knee, Hip, Shoulder, etc. Select the right knee joint and go to the object panel (F7) and click Add Constraint->Rigid Body Joint. Do this twice. In the first constraint, change the field 'toObject' to Right_Leg and in the second to Right_Foot.

ss7.jpg (178.69 KiB) Viewed 11033 times

Do this for the left knee. Select one of the hip joints, add two rigid body joint constraints, making the first one Body and second the leg below the hip joint. Do this for the other hip. The shoulders, elbows, and neck are done the same way too. Make the body the first constraint for the neck and shoulders, and the arm for the hands.

When you start the game engine, he should fall over like a rag doll! This concept can be applied to characters by parenting the cubes to the character mesh (like a skeleton) and using vertex groups. Though to make it look good for a detailed character you may need to use more constraints.

[llamalizard]

I must try this. finally, a good way of doing dynamic bodies...would it react to a player hitting it? like, realistically, as in seperate parts moving?


also, how would I do this with a makehuman model?

[hydra_skillz]

Yes, if you hit one part the others are affected realistically. Try adding a cube, make it dynamic, and add an always force in the direction of the rag doll and aim it at different parts . I haven't used this on a detailed character before, but you would need to add constraints to the joints so they won't bend backwards or any way they shouldn't. You can try parenting the armatures to the cubes, so when the cubes fall the armatures go with them and so does the mesh the armatures are affecting.

[Moris]

There's a whole lot of fun stuff to see on You Tube. Just do a search for "Blender Ragdoll" and see the fun.
M

[rewii93]

I've searched hours !!! NOTHING REALTIME !!! The only available technic is to bake the animation (its weird) but their is NO REALTIME (in the GE) The constrain don't work well in the GE, I don't know why. And I can't select a bone and a cube, the armature always go back to object mode (???)

[hydra_skillz]

You could try something like having the cubes control vertex groups on the character so they would be like the armatures (just rigid).