https://forums.autodesk.com/t5/inventor-forum/help-with-dynamic-simulation/m-p/5788788#M363159 <P>Thank you, it looks good. I used 3D constraint to enclose the piston in the cylinder and it seems that it behaves correctly.</P><P>&nbsp;</P><P>I have one more issue.</P><P>&nbsp;</P><P>What I am trying to do is&nbsp;connecting load to that piston. It would be steel structure dragged on top of metal channels (steel on steel, I attached pic.). I want to check what force this cylinder has to exert in order to pull the structure with velocity of 0.7 in / sec.</P><P>&nbsp;</P><P>I set up friction, materials, and I tried to use unknown force feature placed at the piston but when I look at the graph it doesn't seem like the software notice that there is anything connected to the rod. Can you advise how to make this work?</P><P>&nbsp;</P><P>Thanks, appreciate your help</P><P>&nbsp;</P><P>&nbsp;</P> Wed, 26 Aug 2015 14:01:35 GMT Anonymous 2015-08-26T14:01:35Z