New Tool Test "Draw Mesh"

https://drive.google.com/open?id=0B5_r9d5SdkIvU0hqVm5fNktmbTg

I was trying to retopo a cylindrical shape using cut and bridge and then generating the mesh with Enter key in order to disable camera projection. When the symmetry was on, NVil threw some errors. Without symmetry enabled, the mesh generates perfectly fine:
https://drive.google.com/open?id=0B5_r9d5SdkIvMm5hbU1yemRqQms

Try this
http://www.digitalfossils.com/Download/NVil-Sep-11-17.rar

Last build seem to be very solid.
There was only one hard-to-explain situation, where I couldn't cut through the reference mesh (even with cut action selected in the Draw Mesh UI) because NVil kept extruding an existing edge (extrude as in Draw Mesh terminology). Upon starting a completely new and blank scene, NVil continued to extrude some invisible edge (probably located where my old geometry from the previous scene used to be) whenever I tried to draw a line.
That I loaded up that previous scene (without restarting the program) and the bug was gone.
Really hard to explain. I'd have to catch it on a video but because it felt random, it will be hard.

It's incredible how fast it is to retopo a model with Draw Mesh.

When snapping is enabled, lines have a tendency of overshooting the snapping target:
https://drive.google.com/open?id=0B5_r9d5SdkIvN2d2ZC1zcWFkanc

Try this and see if fixed.
http://www.digitalfossils.com/Download/NVil-Sep-12-17.rar

When you draw a line across the symmetry plane, you will see a cross point at where the line intersects with symmetry plane. If you draw a line which goes through those points, the line will be marked as symmetry center line when generating mesh.
Also symmetry center line handling is done for extrude and bridge(between closed lines) operations.

Lines still overshoot snap targets sometimes, but the issue with symmetry... is completely gone! Phenomenal work IStonia.
Not a single error related to symmetry plane during my last retopo session.

Try this
http://www.digitalfossils.com/Download/NVil-Sep-13-17.rar

I just began testing the last build and immediately noticed that the bridge action stopped working for multiple existing edges. I can LMB+drag a single edge, but I can't pick start and end edges.

I have renewed the file.
http://www.digitalfossils.com/Download/NVil-Sep-13-17.rar

When snapping is enabled, lines have a tendency of overshooting the snapping target

Fixed.

I just began testing the last build and immediately noticed that the bridge action stopped working for multiple existing edges. I can LMB+drag a single edge, but I can't pick start and end edges.

Fixed.
Thanks!

While I'm testing further, I thought I'd file a feature request.
Can you let us drop primitives on frozen reference objects when retopo mode is enabled?

I don't understand what you mean?

Well you know - primitives, like sphere, cube, and so on have a little "Drop" checkbox in their settings window. By enabling it we can drop the primitive directly on a surface of another object. It will also change its orientation according to that object's surface normal.
We can't however drop primitives on frozen reference objects, and this is why I asked about this feature.

Some weird random bug. Disappears after NVil is restarted:
https://drive.google.com/open?id=0B5_r9d5SdkIvYzhVTDFJNWprVzA

I have no clue how that can happen. Can you reproduce it?