This is my TPU retraction test. There are many like it but this one is mine.

I was trying to calibrate 75a TPE for my drag racer tires and standard retraction models were not cutting it for me. So i hopped into cad and made this little thing up.

Print it, check for excessive blobs or pock marks, adjust settings, repeat.

Easy. I was able to calibrate the TPE to print a significantly nicer model in ⅓ the time of the first tire.