ExtrudeShapeCustom not working right

[Sholand]

Hi, I am trying to extrude a polygon using ExtrudeShapeCustom.

I need to use this because I need to access the scale function.

It seems that a polygon with concave shapes messes it up.

code: var c = BABYLON.Mesh.ExtrudeShapeCustom("name", polygon, path, Scale, Rotation, false, true, 3, scene);

When creating the same with below polygonMeshBuilder it works.

var c = new BABYLON.PolygonMeshBuilder("name", polygon, scene).build(1,depth);

My issue is that I need to scale down so the polygon gets smaller as it extrudes.

Is there a fix for this?

I have attached screenshots of the polygonMeshBuilder (which looks ok but without any scaling) and the ExtrudeCustomShape (which is messed up) 

[jerome]

PG please ?

[Sholand]

Hi Jerome,

Here are the two playgrounds

This is the one with the extrudeshapecustom.  I think it is a cap problem.

http://www.babylonjs-playground.com/#KCFUE2#1

Here is the one that works - (but no scaling function available)

http://www.babylonjs-playground.com/#HVQS9P#1

[jerome]

yes, the capping process is quite simple and based on the computation of the barycenter only (not a real triangulation algo) ... something that could be improved actually.

For now, if you need a better cap, you could build a polygon from the shape that you extrude (with http://doc.babylonjs.com/how_to/polygonmeshbuilder) or that you use JohnK's polygonExtruder 

[JohnK]

 Here is link for extruding polygon http://doc.babylonjs.com/how_to/parametric_shapes#extruded-non-regular-polygon

[Sholand]

Thanks for the help...

Until the cap can be improved, can you think of anyway to replicate the scaling function of extrudeshapecustom where the polygon gets smaller (with a proper cap)?  See how the sides taper down?

[Sholand]

Hi Jerome and JohnK,

Is there anyway I can request the improvement of the capping algorithm for extrudecustomshape? or pay someone to do it?

I really need to be able to run the scaling function to taper down the sides.

I appreciate your help and feedback.

Thanks!

 

[JohnK]

As an alternative extrude without caps use createPolygon or PolygonMeshBuilder to make the caps and merge the meshes.

[Sholand]

Thanks JohnK!

Not exactly sure how to do this but I will give it a try...

[Sholand]

It seems that extrudecustomshape and polygonmeshbuilder come out on different planes.

Can't figure out how to line them up...

http://www.babylonjs-playground.com/#KCFUE2#2

[JohnK]

Bit trickier than I thought but here it is https://www.babylonjs-playground.com/#KCFUE2#3

 but I may have got it upside down so https://www.babylonjs-playground.com/#KCFUE2#4

Note that because your poly data is all positive and scaling is set at the origin the shape is skewed see better with bigger chamfer  https://www.babylonjs-playground.com/#KCFUE2#5

If you want to the base centres in alignment then you need to adjust your data to have the origin at the centre https://www.babylonjs-playground.com/#KCFUE2#6

[Sholand]

JohnK, that is amazing!  Thank you for your help.

The last one https://www.babylonjs-playground.com/#KCFUE2#6 looks the best.

How would I go about reversing it so that the bigger surface is on top? so that it tapers smaller down instead of up?

[JohnK]

Easiest way is to do what I did in #4   reverse lower/upper (top/Bottom) values

https://www.babylonjs-playground.com/#KCFUE2#7

[Sholand]

Thanks!  I will try and integrate into my application.

[Sholand]

JohnK - it worked perfectly.  Thank you so much for all of your help!