# First Steps with RL on Linux # rlPlanDemo problem?

[ExplorerFzw]

dear author,I want to study rl project. I followed the "First Steps with RL on Linux" example on the official website, and both the rlViewDemo and rlCollisionDemo ran normally without any issues. However, when I ran the rlPlanDemo, the display appeared as shown in the figure below.

The same issue occurred when I ran rlCoachKin & rlCoachMdl. When I ran rlCoachKin, it displayed a black screen similar to rlPlanDemo, while rlCoachMdl showed normally.
I compiled and installed the source code according to the instructions at https://www.roboticslibrary.org/tutorials/build-ubuntu/. My system information is as follows:

[rickertm]

Are there any errors or warnings reported when running rlPlanDemo or the other demos from the command line? According to #90, setting the render buffer type to single might help.

This could also be related to Wayland, as Coin3D currently has an open issue with this. You can try starting rlPlanDemo etc. with

QT_QPA_PLATFORM=xcb rlPlanDemo

as a workaround or switching to "Ubuntu on Xorg" during login.