HUD overlay flickering


i wanted to report issue during dynamic drawing in the viewport in v6. It is clearly visible when using my last plug -

Whatever is transformed to screen space gets nasty flickering. Below code is enough to get flickering:

protected override void DrawForeground(DrawEventArgs e)
            var s2w = e.Viewport.GetTransform(Rhino.DocObjects.CoordinateSystem.Screen, Rhino.DocObjects.CoordinateSystem.World);

            var cir = new Circle(350);
            e.Display.DrawCurve(cir.ToNurbsCurve(), Color.Red);

In v5 it works without any issues.

@pascal would you mind to tag here the appropriate person to fix this?

Hi @D-W,

I’ve loaded your plug-in on two different systems and have not see the flicker you describe. What am I missing?

– Dale

Hi @dale !

Umm … That’s indeed weird @Pitti & @nathanletwory and i ( on two separate systems) have the same issue in v6 that lines start to flicker when panning/zooming/rotating. HUD text also.

Please open moderate/bigger model run FH with any grid and orbit zoom pan and if it doesn’t flicker it’s indeed weird.

I’m on: Rhino 6 SR15 2019-5-28 (Rhino 6, 6.15.19148.13161, Git hash:master @ ae191a06e4addc9964c3f4231a3312f38d4153d0)

Hi @D-W,

Can you provide a model and instructions on how to repeat the flicker?


– Dale

Sure @dale

Try this one - 3DLenta_NYC.3dm (3.4 MB) - (Leaving credit to original one ->

On Framing Helper toolbar click left and right on those red marked buttons for eg. and only right click on blue marked button and change color to red for more contrast - after picking right click to confirm change.


Here is vid what i get:

@D-W - correct me if I am wrong, but I’m not seeing a “flicker” but rather curves being dropped during view rotation. Is this correct? @jeff, can you add anything here?

– Dale

@dale i don’t see much difference in “flickering” and quick dropping and showing curves from viewport during camera movement (?) - maybe my English is not precise - lines are randomly showing and hiding during dynamic draw - is it now correct?

From my observation this occurs only to geometry transformed to screen.