Getting a piston to work in a Solidworks motion study

Hey all.
Our CAD specialist is having trouble in Solidworks that is really slowing our project down. He’s doing his best to make a basic motion study so he can calculate the trajectory of our ball without having to adjust our actual prototype. But, to pinpoint his problem, “I can’t get the pistons to move.”
Can anyone post either a written or video tutorial on how to run a motion study with pistons?
(We download our pistons from
Thanks a lot, this is exceedingly frustrating.

If you right-click on a part in the piston sub assembly, and click “select sub-assembly” and then right-click in blank space, there should be an option to make the sub-assembly flexable. This should allow the piston to move.

Can you give anything more specific to the motion study feature? Like, getting the piston to operate by itself?

I have actually not used the motion study feature, so I cannot give you more information than getting the piston to move in another assembly.

You need to give a bit more info.

Does the cylinder come in as an assembly or a single part?

If assembly, can you separately select on the piston? If a part we have more work.

Is the cylinder cylindrical or square?

The base of the cylinder must be fixed. The piston must translate through mates. Usually a concentric mate is good to start.


Hi, im the main CAD worker for team 5236, I have a cylindrical piston, it has all correct mates and is connected to what it should be pushing. I can make it move with the rotate component tool. It is a sub assembly in the full assembly and it is flexible so it slides with the rotate component tool. I just cant seem to figure out how to use motion study. I also cant seem to find a video that would help me with this


A few things. I downloaded a Bimba cylinder from The rod is free to translate. Make certain this is your case in the assembly.

There are three forms of animation/motion.
If you want path/trajectory/force, you need to Add In SolidWorks Motion,

I highly recommend you review two SolidWorks Tutorials ‘SolidWorks Animation’ and ‘SolidWorks Motion’ under Help>SolidWorksTutorials.

You can perform basic motion under “gravity” from the motion tab. The Linear motor is available- but the cylinder has no straight edge, so you will need ot insert an Axis, under Insert, References, Axis.

For motion analysis (kinematics) you need to add in SolidWorks Motion and then select Motion Analysis from the Motion Manager. Select Linear Motor. Select the cylindrical face of the rod and the direction. Click inside the Component to Move Relative to box and click the housing of the cylinder.

I went on the Brimba website and 3dcontentcentral but I do not know which assembly was used. Could you please provide a link to the piston assembly that is being used? I could be more helpful if I see the problem myself.

I downloaded a Brimba piston assembly and all of the parts were fixed (had a (f) next to their name). To solve this issue just right click and pick float. You might then need to create some mates. Also, the mates in the assembly might be restricting the piston from moving. You can right click on a mate and suppress it to see if it is restricting the piston from moving. This is a bit like deleting the mate but SolidWorks keeps track that the mate was created and it is easy to bring back suppressed mates by right clicking and picking unsuppress

I have created a few videos. I hope these help.

If this does not solve your problem, could you please tell me what you want the motion study to do with the piston besides just move it. As in what do you want to analyze or what results you want to obtain from the motion study? If the problem is in getting the pistons to move, I would be happy to look at the assembly and make a few suggestions.

First ensure that the piston can be properly actuated in its own subassembly. Ones downloaded from the manufacturer should do this. Then make sure it is properly defined in the full assembly. Finally change the solve as property of the piston sub assembly from lightweight to resolved. Look that up in the Solidworks help page for more details. Once you do this you should be able to use the normal motion study actions on the piston.

Hope that helps. Otherwise I may be able to post better instructions when I’m on my workstation later.

Edit: right click on the piston sub-assembly and go to component properties. Ensure the suppression state is set to resolved. If it is not change it and save. The change the “solve as” to flexible. Any parts that can move/actuate in the sub-assembly should now be able to do the same in the full assembly.

Sorry for the lack of replies, everyone. Our CAD man’s been sick. I’ll have him post as soon as he’s here.