Bushing coordinate mismatch in Kinematics (LTS 2026 Geometries)

Vehicle Modelling IPG Kinematics
1

Hi,

I’m new to Carmaker and have run into some errors that I’d like some help with. I was running IPGKinematics on the rear suspension geometries provided for the LTS 2026 competition and noticed a consistent warning during kinematic simulations (see photo below):

“Parameter: Point Bushing Center X = wrong!”

Looking into this, the issue seems to be that the parameter-defined coordinates differ from the geometry used internally (usually ~10 mm in Z). In graphical analysis, the suspension uses the geometry values, not the parameter values.

This behaviour appears across the few geometries I tested:

R2_CP0_TP0.kin
R3_CP0_TP0.kin
R4_CP0_TP0.kin
R5_CP0_TP0.kin

I have a few questions:

  1. Doesn’t this mismatch affect the simulation results (e.g. roll centre movement, camber gain, etc.)?

  2. Are the parameter coordinates effectively ignored in favour of the geometry coords?

  3. Is this expected behaviour for these models, and can the warning be safely ignored?

I want to make sure I’m interpreting the suspension geometry correctly before using the results for further analysis.

Thanks in advance.

Screenshot 2026-04-08 134113
Screenshot 2026-04-08 1341131599×805 253 KB

2

Hi fcm.user_26.

  1. No, the IPG Kinematics setting used in the competition excludes compliances.
  2. Yes, this is possible to verify by changing the value and comparing the outputs with Beyond Compare.
  3. The warning can be safely ignored. Please note that the ground truth in this competition is the .skc files which have been provided already. These are what will be used in the virtual competition and the .kin files are provided for your investigations only.

Hope this helps,

Tim