The perspective grid is impossible to set up precisely. You can not adjust the grid to an image to draw over it, especially when the vanishing points are outside of the canvas, which is the case most of the time. The horizon can not even be locked to keep it straight while moving the vanishing points.
For example: importing a picture of a 3D model, placing vanishing points and the horizon of the perspective grid based on the 3d model and drawing over it in the correct perspective. That does not work in Artstudio pro.
Solution: There are plugins that solve it beautifully by tracing the lines of the image that converge to one point, which are then being used to accurately calculate the true vanishing point and the perspective grid is set up automatically.
This is how it works (not the part with the windows):
https://gumroad.com/l/MESl
Please make that available in Artstudio pro, I work a lot with 3d models as underconstruction and need to draw over them with the perspective snap function, but no app on iPad let’s me set up the grid precisely.
