Piston problem

Hi all, I am fairly new to 3DS max and trying to create a small animation of a piston pump. I have the shaft and piston moving in the correct motions using an expression controller, I just cant seem to get the arm working in sync with these. I have used various methods such as look at constraints and changing the order of links to try and solve the problem. I have uploaded the file for the scene to the website below, any advice is appreciated, thanks.

S

http://www.sendspace.com/file/p7os5m

ouch, an engine in 3ds max requires advanced rigging. its simple with an animated character but a mechanical object like an engine will be tough

I could not download your link bu if you are trying to animate the motion of a piston I suggest you look at the IK (Inverse Kinematics) tutorials. You can go several directions with IK either using Solvers and/or bones. IK for mechanisms is a real bear in Max (a piece of cake with Inventor).

a piece of cake for lisp for 2D acad

crank.lsp

Cute, but more work than eating cake. It seems that your code needs something like the VBA DoEvents function to force a screen update in each iteration of the while loop. I am not that familiar with Autolisp. Running it on 2012 I could only see the crank at about 100° increments. Setting a breakpoint in the loop did let me see the incremental rotation.

You can slower down the motion or make it faster by changing the number in line 30, where it says:

(setq	u1   0.5; step in degrees, adjust speed to your CPU here, faster - higher number