# Setting "PN Tessellation " on terrain mat crashes editor **URL:** \ **Category:** Rendering\ **Tags:** editor-crash, unreal-engine, bug-report, tessellation, question\ **Created:** [February 4, 2015, 3:29am UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941 "2015-02-04T03:29:26Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Chaoss](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Chaoss](https://forums.unrealengine.com/u/Chaoss)\ **Post date:** [February 4, 2015, 3:29am UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/1 "2015-02-04T03:29:26Z")
Flat tessellation works fine, however setting tessellation to “PN Triangles” on terrain material crashes editor once the material loads up. This is reproducible on a blank project by simply creating any old landscape, opening the material and setting Tesselation to “PN Triangles”, apply the material and as UE4 loads the material into the scene the editor crashes ---
**Author:** ![Lovecraft\_K](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Lovecraft\_K](https://forums.unrealengine.com/u/Lovecraft_K)\ **Post date:** [February 4, 2015, 7:02pm UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/2 "2015-02-04T19:02:49Z")
Hey Chaoss - Can you post a screenshot of your material which causes this crash? Thank You Eric Ketchum ---
**Author:** ![Lovecraft\_K](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Lovecraft\_K](https://forums.unrealengine.com/u/Lovecraft_K)\ **Post date:** [February 9, 2015, 7:06pm UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/3 "2015-02-09T19:06:38Z")
Hi Chaoss- We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you are still experiencing the issue you reported, please respond to this message with additional information and we will offer further assistance. Thank you. Eric Ketchum ---
**Author:** ![Chaoss](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Chaoss](https://forums.unrealengine.com/u/Chaoss)\ **Post date:** [February 21, 2015, 8:07am UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/4 "2015-02-21T08:07:13Z")
I don’t have the material handy, but it is very easily replicatable, you create a blank material for your landscape, apply it to a new landscape object and set your material to Tessellation with PN triangles. ---
**Author:** ![Lovecraft\_K](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Lovecraft\_K](https://forums.unrealengine.com/u/Lovecraft_K)\ **Post date:** [February 24, 2015, 8:33pm UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/5 "2015-02-24T20:33:30Z")
Hey Chaoss - Can you confirm what version of the engine you are using and also include a copy of your DXDIAG? So far I am able to apply PN Tessellation to my Landscape material without crashing. ![31001-tessellation.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/a/3/2/a32b7a074850c87476caf7c3e04b4c9d715c36a8.jpeg) Let me know, Thank You - Eric Ketchum ---
**Author:** ![Onyxdeath](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Onyxdeath](https://forums.unrealengine.com/u/Onyxdeath)\ **Post date:** [April 21, 2015, 8:00pm UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/6 "2015-04-21T20:00:49Z")
I’m having this issue with my landscape material as well. I’ve replicated it in 4.7.5 and 4.7.6. When I get home I’ll post a screenshot of the material. I’ve used the same material on a landscape tile with less polygons and it didn’t crash, so it looks like it might be related to polygon count. ---
**Author:** ![Lovecraft\_K](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Lovecraft\_K](https://forums.unrealengine.com/u/Lovecraft_K)\ **Post date:** [April 21, 2015, 8:46pm UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/7 "2015-04-21T20:46:38Z")
Hi onyxdeath - Can you please let me know what your tessellation multiplier is set at and whether you have anything plugged into World Displacement? Also are you check Adaptive Tessellation and Crack-Free Displacement to true? Thank You Eric Ketchum ---
**Author:** ![Lovecraft\_K](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Lovecraft\_K](https://forums.unrealengine.com/u/Lovecraft_K)\ **Post date:** [April 21, 2015, 9:17pm UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/8 "2015-04-21T21:17:41Z")
Hi Chaoss and onyxdeath - Thanks to the new information I was able to reproduce this crash internally and have entered abug report for it, UE-14201. It does appear to be limited to extremely large individual landscape pieces smaller landscapes will not cause the crash. As soon as I hear anything about a fix I will let you know - Thank You both for your help - Eric Ketchum ---
**Author:** ![Onyxdeath](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Onyxdeath](https://forums.unrealengine.com/u/Onyxdeath)\ **Post date:** [April 22, 2015, 4:31am UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/9 "2015-04-22T04:31:17Z")
Hi Eric, I’ve tested as many variations as I can think of with tessellation and each variation crashes it. In one variation I put a 1 in the tessellation multiplier while I had a heightmap plugged into world displacement. in that setup I tried checking and unchecking both Adaptive Tessellation and Crack-Free Displacement. To see if it was perhaps an error with the material I swapped out my tesselation material for MI\_GravelTile\_01 from the Kite Demo and that also crashes it. I’ve also tested a fresh project and it also crashed when using the same landscape with a tessellated material. If it’s helpful I can upload one of the height map tiles I use to generate the landscape. EDIT: Oops! I didn’t see that you had already reproduced it. ---
**Author:** ![anonymous\_user\_550b73f9](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_550b73f9](https://forums.unrealengine.com/u/anonymous_user_550b73f9)\ **Post date:** [April 28, 2015, 7:34am UTC](https://forums.unrealengine.com/t/setting-pn-tessellation-on-terrain-mat-crashes-editor/305941/10 "2015-04-28T07:34:49Z")
Hi guys, I just submitted a fix for this crash which will be in 4.8. It was occurring for any landscape that used more than 1x1 subsections. If you’re using source code, the fix is here: [https://github.com/EpicGames/UnrealEngine/commit/35064cbda6c21e261750ecd24b3a0b576daa8d6b](https://github.com/EpicGames/UnrealEngine/commit/35064cbda6c21e261750ecd24b3a0b576daa8d6b)