Error when using line trace, with start point, under the landscape

There appears to be an error when using Line Trace blueprint node, and the start point of the trace is under the landscape.

Recreatable: yes
Test project Provided: yes

Steps to recreate

  1. When inside the project, in the outliner, click on tcollision
  2. make sure you have the output log window open
  3. drag the tcollision blueprint, while located under the landscape
  4. The output log will show that no collision is ocurring in either direction
  5. Drag the tcollision such that it is under the Mesh Floor that is up over the landscape
  6. The output log will show, that the collision is passing through the landscape, and hitting the floor

To show that the landscape is responding, if the blueprint is above the landscape

  1. Simply drag tcollision above the landscape, and move, monitoring the output log.

Location of the test project

Note: The blueprint project (3rd person blueprint) had a lot of it’s starter content removed, as it was not needed for duplication, nor did I wish to upload 600MB of assests not germane to the error.

Hi Jayice,

Landscapes have different settings and limitations to collision than your standard static mesh. Landscapes currently do not support double sided collision which is why the line trace only registers on the top side. I can put in a feature request for this if this is important but keep in mind that specific features like this typically don’t get prioritized unless there is a lot of community interest.

Let me know if that helps,

Ed

It works in version 10. So at a minimum this is a regression. When the spline is under the landscape in Version 10, it does report a hit.

I don’t wish to appear to be argumentative, but for me this is important, if you wish me to chase down where this changed from working, to not working, please let me know.

Jay

The regression occurs between Epic Version 13 and 14. I have verified that the line trace works as expected, in versions 10 and 12 as well. I skipped version 11.

Besides being a regression, there are definite use cases where a player may be under a landscape. Consider cutting a hole in the landscape, to enter into a cave if you will, and then wanting to have a trace going up to know where the top of the cave is, relative to the player.

Blueprint for Version 13

Thank you for your help!

Jay

Any news concerning this? Or need me to do anything else?

Ed,

Thank you for your help, it’s an ease of use issue for me as well, but I also needed the tracking number for the report for my customers.

Thank you for your help!

Jay

IceWare Inc.

Hey Jayice,

Thank you for pointing that out I’m actually surprised something like that worked before. I have reproduced this issue and logged a report for it here: Unreal Engine Issues and Bug Tracker (UE-39819)

You can track the report’s status as the issue is reviewed by our development staff. Please be aware that this issue may not be prioritized or fixed soon.

Cheers,

Ed Burgess