Project 2D screen point to 3D plane - Forum Open Cascade Technology

Guillaume CHAFFAROD
Thu, 02/29/2024 - 17:42

Forums:

Hello community.

Today, I'm trying to create a custom manipulator and I'd like to know if there is a way to project a 2D point (mouse position) to a 3D point that is on a specific plane (using gp_Pln for example) regardless of the camera eye direction.

I know the "Convert" function of the view but there is nothing to convert the 2D point on a custom plane.

Thank you for your answers ;)

gkv311 n
Fri, 03/01/2024 - 09:58

What do you mean 'project 2D point on the screen to 3D space regardless camera eye direction'? That makes no sense to me - camera eye direction and vertical axis are defining the very coordinates system of this 2D space relative to 3D space.

Guillaume CHAFFAROD
Fri, 03/01/2024 - 11:36

Thank you and sorry for my bad explaination.

I have a 3D view. On this view, I have a virtual 3D plane defined by a point and its normal.

I'd just like to know where is my mouse cursor on this plane, using the mouse coordinates and the plane definition (using a gp_Pln for example).

gkv311 n
Fri, 03/01/2024 - 12:05

You may use IntAna_IntConicQuad to find intersection between line gp_Line and plane gp_Pln.

int theX = ..., theY = ...;
Handle(V3d_View) theView = ...;
gp_Pln thePln = ...;
...
Graphic3d_Vec3d aPnt, aProj;
theView->ConvertWithProj (theX, theY, aPnt.x(), aPnt.y(), aPnt.z(), aProj.x(), aProj.y(), aProj.z());
gp_Line aLine (gp_Pnt (aPnt.x(), aPnt.y(), aPnt.z()), gp_Dir (aProj.x(), aProj.y(), aProj.z()));
IntAna_IntConicQuad anIntTool (aLine, thePln, Precision::Angular(), Precision::Intersection());
if (!anIntTool.IsDone() || anIntTool.IsParallel() || anIntTool.NbPoints() < 1) { error }
gp_Pnt aProjPnt = anIntTool.Point(1);

Or you may use picking information, if your plane is defined by AIS interactive object.

Guillaume CHAFFAROD
Fri, 03/01/2024 - 12:31

My plane is virtual and there is no interactive object to define it, but I'm interest on how to do that :)