assembly constraints not valid in dynamic simulation??

Hi..i'm quite new to inventor and using inventor 2009 trial version..

when i'm starting my dynamic simulation for a given mobile component ..all the assembly constraints applied on that component previously - like angle constraints - are getting lost... if it is the general case than how to avoid this??

further can someone provide some tutorials dedicated to dynamic simulation explaining the theory of joints in inventor..

thanx for ur help

The first time you open dynamic simulation a box should(or should have) popped up asking if you would like a tutorial. If not the help menu has a few tutorials for you.

In dynamic simulation any driven constraints will need to be redone. Things like coincident and concentric constraints(which allow movement but dont drive it) will be vaild. When you are in the Dynamic Simulation you will be able to Insert Joint. This is where you will find all the "constraints". The screen shot is IV11. 2009 and 2010 look a little different but the content is the same. There is an animation with each joint that shows you the selection process. There is also a ? at the bottom corner which will take you to your help. After you create these joints you are able to edit their parameters like degrees of freedom and distance. The is one joint called Spatial that is a free for all. It allows you to tell it which of the 6 degrees of freedom to enable and how to handle them. I would only use this if none of the other joints will work.

Joints in Dynamic Simulation can automatically be applied based on Assembly constraints. Go to the Dynamic Simulation Settings and turn on the automatically recognize joints. Conversely you can also recognize joints off constraints with another command in the browser. You can also create constraints inside Dynamic Simulation by holding Shift+C. The inherent difference here is that with Dynamic Simulation you are granting degrees of freedom instead of restricting it as in an assembly. Some Joints will restrict and some will grant DOFs. If you are really interested in this there is an AOTC book by autodesk that will explain this further or I can give you a simple example start to finish of a Newton's Cradle which may help you understand it better.

Mark, will it recognize driven constraints? In his question he mentions an angle driven constraint. What about Mechanical Constraints? I guess im just wondering if there is a limitation to automatic recognition.

There is limitation to the constraint translations. Driven constraints can only be done in the Assembly environment and do not have a 1:1 match in Dynamic Sim. Transitional and Motion constraints do map over however. The other horrible characteristic of this is that the automatic is an all or nothing translation and if you turn it off after recognizing 10 joints and adding your own personal 5, then you lose all 15 not just the 10 that were recognized.

I see thanks for the clarification. Before I use Dynamic Sim I always suppress any constraints that are driven or Mechanical and I think I will continue to do so.