My ambition knows no bounds. I'm attempting to animate a mechanical walking beast with a large number of interacting machanical parts (Mainly joints driven by hydraulics). Most of the joints are comprised of repeating structures, for reasons of aesthetics and because of the inherent limitations of the pistons "driving" the joints (They're actually following the joints!). For instance, the legs go: "Double Spherical Joint (+/- 30 deg H,P (0 deg B))" --> "Parallel Kinematic Shoulder Joint (+/- 30 deg H,P,B)" --> "Hinge +60 deg P, 0H, 0B" --> "Hinge +60 deg P, 0H, 0B" --> "Hinge +60 deg P, 0H, 0B" --> "Parallel K Ankle" --> "Toes" In reality, the PK joints at the shoulder and ankle are capable of motion in all six axis, but getting an IK chain to work that way seems impossible, but this is tangential to the topic of my post. The real problem with the mechanics comes from calculating the IK chain on this bad boy with all the associated doodads and gewgaws that go along with it. As an example, the shoulder and ankle require at least 4 hydraulic pistons each. Each piston comprises two object layers and two null objects. Each hinge joint is constructed from a piston, with a mechanical linkage that scissors the section of leg open. The scissors requires at least 2 object layers, and two nulls. Then add in the "spine" of the creature and the IK chain gets unbearably long and you being to see the problem I might be having in animating the critter. Calculating the IK chain is taking 60 seconds per frame on a P4 2.5ghz machine! Rendering a small 640x480 test render of the frame takes 6 seconds with IK turned off, and 66 seconds with it on! I guess the answer to: "How am I going to animate this!?" is: "Very carefully." My question is, what would you reccommend as a solution? Joint driven morphs? Seperate IK chains between the legs and the spine? Giving up and moving to Canada?

Forum: Animation

Subject: IK difficulties