CoppeliaSim forums

As for the values of the DH parameters theta and alpha between the joints shown by coppeliasim, I set two parallel joints, one of which rotated 90° around its own X-axis, indicating theta=180° and alpha=-90°. But when I still set the joint to rotate 90° around its own Y axis, indicating that theta=-90°,alpha=-90°, the method of judging theta and alpha values is different from the improved DH method, I don‘t understand how the values of theta and alpha are obtained. Around which axis are the theta and alpha values respectively obtained?