MSPhysics in Sket6chup 2017
-
I built the model of what will be a table saw carriage that I wanted to test the geometry of in MSPhysics but when I start a simulation the model sits there for a couple of seconds then it just kind of blows up and pieces just sort of fall all over. Can anyone tell if it's because of the way I built the model or if I need to change the shape parameters in MSPhysics or what. I would appreciate any help on figuring out how to make my model function the way I intended it to as I have many more plans to test using MSPhysics
-
Hello, Trent Perez,
First rule: Groups that should act as one object must be grouped into another group. In your model, you should endup having 3 groups; the frame and two arms.
Second rule: Groups that have concave geometry must be divided into convex sub-groups. If you enable the collision wireframe you will see whats wrong. Basically, one of the arms must be divided into two sub-groups, even though that's not how it will look when you go about designing it.
Here is how the fixed model should look like:
Table Saw Carriage test V1.0.skp
I also enabled and adjusted min and max limits for the two hinge joints for a more proper behavior.Regards,
Anton -
That's great! Thanks for that. Now I have but one more problem. I want to put a bolt through the hole in one of the arms that slides through a slot cut in the other two arms. Is that possible to do and if so how do I set it up? how do I get the bolt to ride in the slot of the two arms because right now when I put the bolt in and group it with the single arm it pops up above the two arms I imagine because I don't have the geometry correct but I am noty sure how to accomplish it correctly.
-
Yes, you're correct, the collision geometry covers up the hole, as MSPhysics generates convex collision for all linked faces. You can fix this by subdiving the group even into more convex sub-groups, like in the image below:
For more accurate convex subdivision, you can use Convexify by fredo6.But then, either way, your model will endup with multiple geometries, ruining the view. What you can do about it is have another, hidden layer, calling it "MSPhysics Collision", where all the convex subdivisions will be stored. Then have the original, non-subdivided versions of the groups be visible and set to MSPhysics->State->Ignore, so they don't interact with MSPhysics simulation.
Here is how it should be:
Table Saw Carriage test V1.0.skp
You can enable the "MSPhysics Collision" layer to see the collision used for simulation.
Advertisement