Constraint's Linear Velocity Target Ignored When Zero

Development World Creation
, , , , ,
1

Running the latest binary build from the Epic Games Launcher:

4.7.6-2513093

To Reproduce

  1. Download ContentExamples project
  2. Open the level “Physics”
  3. Edit any constraint component, I found the ones on board 1.7 convenient
  4. Ensure all angular motion is locked, and only the z axis (which should be facing upwards) is free to move at least 200 units. This step does not seem necessary, but will make the bug more readily visible.
  5. Configure the Linear Motor as shown in the image

39644-springbug.png

The problem is that when “Linear Velocity Target” is set to 0.0, Linear Velocity Drive is not applied, and the box’s motion is not dampened. These steps have been reproducible for me.

The quickest work-around seems to be to set the linear velocity target to a small non-zero value, like 0.1 instead.

If this is a documented quirk, and not a bug, I’m very sorry. I am rather new to this engine, and may have missed some documentation.

Currently running:

Windows 7
AMD Phenom II
4GB DDR3 (below spec, I’m sorry T_T)
NVidia 550 Ti

2

Hi RockSoldier,

Thank you for the report. I was able to reproduce this behavior so I’ve created JIRA UE14395. Our developers will be investigating further and we will post back here with updates.

I also spoke with one of our developers about this. So in the Linear Motor section, a zero value is considered disabled/off. As a workaround, you will need to use a small value like .001 to get the effect that you want.

Cheers,

TJ

3

Hi RockSoldier,

Our developers added an additional checkbox to completely disable an axis and the zero value will now actually apply the correct amount of dampening.

42564-linearmotor01.jpg

You should see this working properly in a future update.

Cheers,

TJ