Continue to Site

Welcome to 3DCADForums

Join our CAD community forums where over 25,000 users interact to solve day to day problems and share ideas. We encourage you to visit, invite you to participate and look forward to your input and opinions. Acrobat 3D, AutoCAD, Catia, Inventor, IronCAD, Creo, Pro/ENGINEER, Solid Edge, SolidWorks, and others.





Great forum you have here. I'm drawing an engine for model airplanes. As you know, it as springs that close each valve independently. My question is if it is possible to simulate, not the spring deformation, but its effects when running animation? I dont even know if Catia can animate an assembly...:confused: so please escuse me anything...:D
Last edited:
yes you can make animations on catia

it is possible to make animations by using catia. but i have no idea about springs.
You can make animations by using DMU KINEMATIKS.

1. You must use constraints at assembly modelling
2. u must determine first motion or motions
3. You must be carefull for degrees of freedom of mechanism. (also catia warnings you)

Also you can make movies of these simulations...
limited time for tell more:(
Last edited:
Thank you very much!
Hope, I can make that spring effect thought:rolleyes:


CATIA has two products that simulate the motion of parts in an assembly: DMU Kinematics and DMU Fitting Simulation. However, both of these tools analyze the motion of rigid parts only (no springs), and ignore forces (loads, restraints, gravity, etc.)

As Spider007 as posted, there are some ways you can 'fake' a compression spring in Kinematics.

If you want to get a true animation, you might want to consider a CATIA add-on product called LMS Virtual Lab.
LMS Virtual.Lab is definetly usefull!!
Mr. CATIA, I'm modelling a simple four stroke motor for those small airplanes. As you know, for closing the valves on each stroke I need to have the spring force acting on the arms (which close the valves), right? You said I CATIA ignores forces... so I really need LMS Virtual.Lab, don't I? :eek: Isn't there another solution? Like using parameter of relative motion?
The answer to your "do I really need LMS Virtual Lab?" questions depends on how accurate an animation do you want, and how much time do you want to spend in trying to make it work with kinematics. And what software do you have access to?

Yes - you can definitely animate the engine movements with DMU Kinematics. And you could "fake" the spring compression, but you'll have to define a spring-arm linkage to get around the driving force of the spring. You will probably have to add some dummy parts (that you'll hide during the animation) to "fake" the true engine behavior.

Another method? With CATIA? I guess you could animate a 2D (cross section) stick figure by using a sketch and the ANIMATE CONSTRAINT tool.
I only have CATIA for now...But I should think about getting LMS V.Lab...I just need to put all parts in motion while rotating the crankshaft
Mean while I'll try with DMU Kinematics...Is it very time-consuming?:confused:
(Thanks all, for your help)
Hello,you can manage by DMU Kinematics

There are some ways to start in DMU Kinematics.
1.Firstly make in Assembly workbench Constraints perfect.!Fix Parts,Coincidince,Contact etc.
Then switch to the DMU Kinematics,There is a Command "Assembly Constraint Conversion".This will automatically converts your constraints into Kinematic commands..Then you can "simulate" and save as "avi or media player formats" by means of "compile simulation"...

2.Use ordinary DMU Kinematic commands and perform above actions again...

Articles From 3DCAD World