I am trying to make a CSYS based on Absolute CSYS using option "Z-axis, X-axis, Origin". To set X-axis direction, I pick the option "At Angle to XC" and use previously defined expression (called XCangle).
The new CSYS is located propperly, but when I try to edit the expression afterwards it does not work. When I edit the new CSYS, it shows that X axis vector is fixed:
So the connection to the expression has been lost (or never established?).
Could somebody explain this unexpected behaviour? Maybe I am doing something wrong.
I know I can make it associatively with "Offset CSYS" option. I am just wondering why it does not work with "At Angle to XC" option.
Thanks in advance!
Solved! Go to Solution.
XC (also YC ZC) creates an angle between your choosen value and the WCS(WorkCoordinateSystem). The WCS by itself is always fixed in the ABS (Absolute Coordinate System).
In every dialog and feature where it is possible to choose XC or YC or ZC you can see that choosen vectors or points ect... are fixed after leaving the dialog.
To explain why this behavior is very difficult, I suggest to you a workaround that allows you to achieve what you want.
First you have to define the X axis 'By Expression', this defines a variable 'vector(1,1,0)', then you have to define variables, as I show you in the attached image, and replace the (1,1,0) value whit this.
Note that this definition is based on absolute Xc not on Datum CSYS feature.