Failed to use CSG function to add a hole on a mesh created via CreateRibbon function

[JZ7878]

Hi all,

I want to add a hole one a mesh which created via CreateRibbon function (the mesh itself is a bit complext, but I simplify in the demo).

Following the demo http://playground.babylonjs.com/#T6NP3F#0 I create a demo, links is http://playground.babylonjs.com/#J4H6RF 

but seems it will failed to do the subtract operation on the mesh created via CreateRibbon, any one can help me on it?

 

If I want to add a hole on this type of mesh, which is the better way I can have a try ?

Thanks in advace.

[JohnK]

Hi @JZ7878 and welcome to the forum from me. The issue is the use of double sides for the ribbons. To ensure the normal directions for the sides are correct (ie point away from solid) to produce the 'solid looking' mesh you need to swap the order of some of your arrays. I have done this by using the reverse function but you could change the appropriate arrays by hand. The 'direction' of the ribbon will also affect how CSG works. So here is a cube made up of single sided ribbons in correct direction

http://playground.babylonjs.com/#J4H6RF#3

You can also remove the backface culling lines.

I stuck to using a standard box as it was easier to experiment with just one 'ribbon cube'.  You can try the same approach with a 'ribbon hole maker' making sure normals will be correct.

[JZ7878]

@JohnK

 

wow, thanks very much,  that's realy what I want, you make me better understand it,   and I will try it right now.