Point Picking on Wireframe Planes

[c3kkos]

Hello there

very happy CloudCompare user here.

I'm using 2.13.2, the point for this topic is:

Point Picking do not work whenever a plane (from primitive factory) is visualized as Wireframe.
That DO work when that very same plane is then switched back to "solid" vis (turning off wireframe flag, which is off by default)


This is clearly useful in scenarios where the solid plane gets in your way from picking points that are beyond, hence not in clear line of sight


I hope this is not a work-as-intended mistaked one :)

Thank you all

[c3kkos]

Ah!

forgot to say that plane's vertices are all set to "visible"

[daniel]

Ah, it's more a limitation due to how we manage point picking (by looking at whether the click intersects the entity in 3D, but not at how this entity is displayed). Basically any kind of transparency is not supported at the moment :(

[c3kkos]

And that makes sense.

I think:

a workaround might be to (internally) generate, replace and display a set of polylines TO MATCH the plane, when the wireframe flag is ON.
As basic as it sounds, a plane: 4 vertices, 4 lines..

Point picking with those entities should work well with that

[c3kkos]

Up! i've read once again this and thinked it can be simpler than that...

just handle the vertices as points (regular plain "point cloud" point) WHILE in wireframe mode

[daniel]

So I looked into this, and I realized there was an issue: if an entity was below a mesh displayed in wireframe mode, no picking would happen.

I fixed this, and then I updated the picking mechanism to 'simulate' picking directly on the wireframe. I'll let you test with the latest 2.14.beta version online.

[c3kkos]

That's great.
Thank you Daniel

I confirm point picking is now working on wireframe meshes.

it works with the tool AND by SHIFT clicking "on the fly" mode.

1.png (26.41 KiB) Viewed 14423 times

I assume that small errors in a strictly defined plane, where the Y is set to 0, and normal is pointing in integer direction, are related to the "gl" graphical mechanism in which the entities are "filtered" into. is it right?

Units in that file are to be considered in millimeters

note:

i noticed that points that are not vertices (or are they?) can be picked in the shortes edge of my plane.

2.png (44.21 KiB) Viewed 14423 times

[daniel]

Hum, strange, but not impossible (especially because I had to 'project' the picked points on the nearest edge). I'll have to look into that.