Adaptive Subdivision problem

I hope this is the right place to post this question, I don’t see a ‘modifiers’ section in the Support category. As I’m only having this problem when rendering, I’m putting it in Rendering support :).


The problem is these high tension wires which appear in the render, which are not part of the mesh.

I have a large terrain mesh, and on it is a Subdivision modifier with Adaptive Subdivision checked. Levels Viewport is set to 0 (and levels Render was set to 0 before enabling Adaptive Subdivision). The issue shows up regardless if Optimal Display is enabled or not.

I’ve attempted to clean up the edges of the mesh, thinking that some jagginess at the edges might be causing the problem. And this did affect it, the ‘wires’ move after deleting some vertices. I also added a solidify, thinking that maybe if it were an enclosed mesh rather than just a planar one this would go away; no change.

Disabling Adaptive Subdivision removes the problem. Using a static number of subdivisions works as one would expect, no weird wires running across the scene. Of course, the microdisplacements are also absent. So in this case, the rocky protrusions of the cliff faces don’t look nearly as detailed as they do with the Adaptive Subdivision enabled.

Has anyone encountered this? Or have any suggestions on how to fix it here and avoid it in the future?

That’s usually related with the UVmaps that once the object is sub-divided get a gap. The Normal map or the Bump map are the ones that causes this issue, color maps usually don’t give a problem.

If is not the UVmap then it may be that the geometry is not connected.