Hey everyone! I'm fairly new to Moi3D but have been following the tutorials diligently.

I was wondering if you could help me figure something out Vitaly Bulgarov related.

In this post here:
https://www.instagram.com/p/Bq9qyZ5B2V4/?utm_source=ig_web_copy_link

In the first few seconds he does something to create a plane at a very interesting angle in order to trim the top off the leg.

I have been trying to recreate this effect but I just can't seem to draw lines like this without the end shooting off somewhere way off in the distance.

I'm clearly missing something really simple here! Can anyone point me in the right direction please?