Draw Mesh with Snap Vertex On makes line jagged

Hi everyone,

I am testing doing a retopo using draw mesh and run into a problem. When I enable vertex snapping, so that my end points stick to existing vertex, because I find that if the end points are not touching the vertex, no geometry will be created, and.. the line I draw becomes jagged because the vertex snapping caused my stroke to snap to vertices on the referenced mesh.

I created a gif to show what I mean...

https://www.dropbox.com/s/pzxzpikgt5cg19v/Draw-mesh-snap-vertex.gif?dl=0

I watched rubberDuck's video and see he doesn't have the problem. Any ideas??

Freeze the reference object.

Ah, thanks IStonia! now it works! nice~

Also make sure this option is disabled, Edit > Preference > Options 2 > Snap to frozen object enabled.