I found out that there is a setting on each joint (as seen in the SketchyPhysics Inspector) called "ConnectedCollide" which is disabled by default. This setting must be checked for objects connected to the joint to undergo full collision checking.

I found out that there is a setting (as seen in the SketchyPhysics Inspector) for "ConnectedCollide" which is disabled by default. This setting must be checked for hinged objects to undergo full collision checking.

@cphillips said:

That is a "feature" of the physics engine. Any 2 objects that are joined by a joint will not collide. I changed it once so they did collide and it caused all kinds of problems. Future versions may have an option.

Has an option been added yet to enable collisions for hinged objects?

(Sidenote - I had trouble finding this post because I was searching the forum for "hinges" instead of "hinge".)

@sythem said:

My current model is just 3 "bars" hinged together. The two on the ends will spin about the hinge but the one in the middle is locked in place by two unmoving hinges. Any clue what I'm doing wrong?

Sketchup Make 15.3.330 32-bit & SketchyPhysics 3.5.6.

Thank you,
Sythem

I tried creating 3 bars hinged together as you described in SketchyPhysics 3.6.0 and Sketchup Make 15.3.330. Did you encounter the same problem I did - that the outer bars can pass right through the middle bar (no collision detection)? Is collision detection broken for hinges? Unless I'm doing something wrong?

3 bars hinged together

The grouping required for making joints seems to conflict with collision detection.

If I do the following:

1. make a joint between object A & B,
2. attach the joint to object A,
3. group the joint with object B,
   then the collision detection for object B gets broken.

In the attached file, I've have linked three boxes, and the two joints are grouped with the box in the middle. Notice that the middle box can pass through the outer two boxes (no collision detection). What am I doing wrong that prevents the middle box from having proper collision detection?

3 objects connected by joints. collision detection for middle object is strangely broken - it can incorrectly pass through the outer objects.