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rlmergeuser
04-23-2012, 10:24 AM
I am trying to implement a simple physics object

A barrel with a plank above it that works as a see-saw as the rider goes across it.

I have made the plank a physics object and locked it to the driving line.

When the rider goes across it works just about, however I want to ensure the object is limited to rotating around one axis. If I go over it more than once the plank is rotated so that parts of it are no longer on the driving line.

I tried using a joint between the barrel and plank, but I get the same problem. However I may be configuring the joint incorrectly.

To sum up, I want to make physics objects that stay straight on the driving line.

Any help appreciated.

Jarr3tt88
04-23-2012, 12:30 PM
Lock to driving line checked?

rlmergeuser
04-23-2012, 12:38 PM
Not really used the editor but would it be possible to lock the barrel in place, but allowing rotation, then clip the plank into the barrel so the plank is locked to the rotation of the barrel.

Jarr3tt88
04-23-2012, 12:46 PM
Not really used the editor but would it be possible to lock the barrel in place, but allowing rotation, then clip the plank into the barrel so the plank is locked to the rotation of the barrel.

Thats not how you would want to do it.

The best would be place a static barrel (any object as a pivot), and enable physics on the plank (any object) Lock the plank to the drive line.

rlmergeuser
04-23-2012, 01:18 PM
Thanks for the replies. Interestingly I have already checked the box "Lock to Driving Line". I think it works after a fashion, as the center of the plank does stay on the driving line, but it rotates about it. I am not sure the correct axis, but imagine one end of the plank coming towards the screen and the other going away, that is the axis I am talking about. It gets to the point where either end are off the driving line and the rider falls off.

It's frustrating, because I have seen many planks implemented perfectly on lots of Trials tracks. There is a simple solution out there I am sure. The easiest solution would be if the "x" axis is the one rotating about the barrel, then "y" and "z" should be locked.

dasraizer
06-28-2012, 09:22 AM
how about making your own invisible hinge, plank with scaffold pole glued to it on the rotation pivot, that's clamped to some invisible object.

rlmergeuser
06-28-2012, 10:18 AM
Just set the angular damping of the plank to 100%, that should do it. If not then physics joint rotational hinge.

Rotational hinge setup- Target 1 the plank, target 2 the barrel. select the pivot and place it just above the barrel but inside the the plank. All other setting of the joint leave default. Be sure physics of the plank is on and the pivot visual axis display (should be a full circle) is at the correct angle. Click the right stick 3 times whilst "holding" it and it should snap to the X axis perfectly IIRC, then just put it in the correct place.

H3X23
06-28-2012, 01:09 PM
i made a see-saw and my pivots centre sat ontop of the see-saw dead in the centre.

rlmergeuser
06-28-2012, 01:28 PM
Use a physics joint and turn joint strength all the way up. Or, glue a dummy object on each end of the plank and lock to driveline.