Point index issue when merging two POPs

Hi!
I have a problem merging two POPs together. I think the issue might be related to the point indices, but I’m not sure.

I’ve attached some pictures and the project file to test it.

In the project, I create a noise texture with a 1:2 aspect ratio. Then I use this texture to distort a plane.

I also split the original texture into two square textures. Then I use these textures to distort two square planes. After that, I merge them together and add a Connectivity POP, a Skin POP (with the Skin parameter set to “Skin Every Nth Primitive” and N set to 2), and a Normal POP.

The problem occurs in the second case. When I merge the two POPs, it seems that the points are not connected in the correct way. You can see this in the first image below.

The red plane is just there to highlight the junction point between the two planes.

In the second image, you can also see on the right side the first plane with a 1:2 aspect ratio.

In the third image, there is another close-up of the issue.
In the fourth image, you can see the same detail but with the Skin POP parameter N set to 7.

The problem is that if I use a higher N value, I lose more of the distortion. You can see this in the last image, where I added more noise to the surface. There is a significant difference between the first plane (on the right side) and the two merged planes.

If I reduce the number of the plane’s subdivisions I can avoid the issue.
However, I would like to understand how to fix this properly and get a good result even with a high number of subdivisions. (In the example images I use 648 subdivisions, but in the project file I set them to 100 using a Constant CHOP.)

How can I fix this?
Do I need to recalculate the point indices of the two merged meshes? If so, how?

Thanks!

20260224 - Debug merge tiles.toe (9.3 KB)

Hello @Mauro

It looks like several factors are preventing the patch from producing a seamless deformed mesh: the Skin POP is skipping every second line strip even though it can use all incoming strips, the two grid meshes currently share an edge when they should be offset by one cell (1/totSubdivisions) and the Noise TOP should match the grid meshes’ resolution to ensure consistent pixel sampling.
Also, the Connectivity POP isn’t necessary if the Plane POPs are already outputting line strips.

20260224 - Debug merge tiles.Modified.toe (9.8 KB)

Thanks @Guillaume.L, you made my cry!! :smiley:

They may look like silly errors, but I think I would never have discovered them without your help , especially the off by one cell offset. I also see that you used “Rows” in the “Connectivity” parameter of the Plane.

Thank you very, very much again. :slight_smile:

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