The driver calculate bad values randomly when rigid body constraint (motor) attached #72042

New Issue

Gabor Horvath · 2019-11-29T11:15:10+01:00

Gabor Horvath commented

2019-11-29 11:15:10 +01:00

System Information
Operating system: Windows-10-10.0.16299 64 Bits
Graphics card: GeForce GT 730M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 389.08

Blender Version
Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-11-20 14:27, hash: 26bd5ebd42
Worked: (optional)

Short description of error
I built a construct with motor constraint and I would like to measure the turn angle with a driver.
I expected exact data but I got right data with randomly errors with 0.0 value.
2019-11-29 10-32-27.mp4

Exact steps for others to reproduce the error

Add two cubes (origins 0,0,0 and 3,0,0) (cube1, cube2)
Add rigid body feature for both
Add rigid body constraints for both
The cube2 rigid body is passive
The cube2 rigid body constraints type is generic (linear limiters enabled with 0's) (Y,Z angular limiters enabled with 0's) the first objct is cube1, the second is cube2
The cube1 rigid body constraints type is motor (angular enabled with def. values) the first objct is cube1, the second is cube2
Add a custom property at cube1 properties pane. (limit range is -1000 .. +1000) (called prop)
add a driver for prop (scripted, 'var' expression, one input variable: rotational difference between cub1 and cube2)
Start the animation with space
10 examine the driver values in drivers editor and got flashing 0.0 values (errors) between the right values.

**System Information** Operating system: Windows-10-10.0.16299 64 Bits Graphics card: GeForce GT 730M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 389.08 **Blender Version** Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-11-20 14:27, hash: `26bd5ebd42` Worked: (optional) **Short description of error** I built a construct with motor constraint and I would like to measure the turn angle with a driver. I expected exact data but I got right data with randomly errors with 0.0 value. [2019-11-29 10-32-27.mp4](https://archive.blender.org/developer/F8177795/2019-11-29_10-32-27.mp4) **Exact steps for others to reproduce the error** 1. Add two cubes (origins 0,0,0 and 3,0,0) (cube1, cube2) 2. Add rigid body feature for both 3. Add rigid body constraints for both 4. The cube2 rigid body is passive 5. The cube2 rigid body constraints type is generic (linear limiters enabled with 0's) (Y,Z angular limiters enabled with 0's) the first objct is cube1, the second is cube2 6. The cube1 rigid body constraints type is motor (angular enabled with def. values) the first objct is cube1, the second is cube2 7. Add a custom property at cube1 properties pane. (limit range is -1000 .. +1000) (called prop) 8. add a driver for prop (scripted, 'var' expression, one input variable: rotational difference between cub1 and cube2) 9. Start the animation with space 10 examine the driver values in drivers editor and got flashing 0.0 values (errors) between the right values.

Gabor Horvath commented

2019-11-29 11:15:10 +01:00

Added subscriber: @hgabor47

Gabor Horvath changed title from ~~The driver are give bad values when rigid body constraint (motor)~~ to The driver calculate bad values randomly when rigid body constraint (motor) attached

2019-11-29 11:16:33 +01:00

Philipp Oeser commented

2019-12-02 11:54:20 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2019-12-02 11:54:20 +01:00

Changed status from 'Open' to: 'Archived'

Philipp Oeser closed this issue

2019-12-02 11:54:20 +01:00

Philipp Oeser self-assigned this 2019-12-02 11:54:20 +01:00

Philipp Oeser commented

2019-12-02 11:54:20 +01:00

Similar to #72107 (The parenting not working right with RigidBodyConstraints (motor)), if you use intermediate objects between the two rigid bodies as constraints (as this is done automatically when you use the Object > Rigid Body > Connect feature), it is fine actually:

#72042.blend

I'll dare to close both of these reports now, it is different from 2.79, but if used as suggested seems to work just fine...
(feel free though to comment again if issues persist...)

Similar to #72107 (The parenting not working right with RigidBodyConstraints (motor)), if you use intermediate objects between the two rigid bodies as constraints (as this is done automatically when you use the `Object` > `Rigid Body` > `Connect` feature), it is fine actually: [#72042.blend](https://archive.blender.org/developer/F8184879/T72042.blend) I'll dare to close both of these reports now, it is different from 2.79, but if used as suggested seems to work just fine... (feel free though to comment again if issues persist...)

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The driver calculate bad values randomly when rigid body constraint (motor) attached #72042