Hello everyone!
I am using Trail version 2016.3.31, and I have some problem creating a circular movement. Here it is:
At first I didn't know the CIRC command and I used SPL command to create a spline close to a circle.
This works fine like the GIF below:

But then when I zoom in I found the pin move like this:

I divide the arc into 100 points, arc radius is 155mm, and robot arm is AGILUS R1100.
The black circle is how I measure the pin displacement, the circle radius is 3mm.
In this case if I divide the arc into 100, the accuracy will be 3mm/150mm.
If I divide the arc into 1000 points, the accuracy will be increased, and the displacement will be less than 0.1mm.
Which I think is OK. But I am not sure if a 1000 division number will reduce the speed of the whole system.
After then I found there is a CIRC command, and it seemed more reasonable than a 1000 division Spline.
I made the GH definition like the picture below:

But the final result is like the GIF below:

Then I checked the PDF named <KUKA System Software 8.3 Operating and Programming Instructions for End Users>
And I found some description like that:

So in this case I assume that no matter what tool I use (I did not try kuka official tool), I can not control the point direction through out the arc, with auxilary plan in GH.
After some research I found this Youtube video:
https://www.youtube.com/watch?v=owyy1g1FHMAI clipped the gif as below:

I think this kind of "fixed pointed" arc movement is very common in robotic arm, and I believe the arm in this video did not use a 1000 division Spline, nor did it encounter some direction problem like my CIRC command.
I am a little confused now.
Is there anything I am missing? Or did I do something wrong.
Please help me.
Thank you very much!