News Forums RAIN General Discussion and Troubleshooting Vertical polys in RAIN navmesh

This topic contains 8 replies, has 5 voices, and was last updated by  KB 1 year, 10 months ago.

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    I am getting lots of vertical polygons in the navmesh even tho’ max angle is 45 degs! Changing the settings in the RAIN navmesh does seem to affect the number of vertical polys and I don’t get them everywhere, lots in some places, nothing in others.

    The scene geometry is very complicated but that should not matter when measuring angles to reject stuff properly.

    Here are the navmesh settings.
    Scale: 60 x 10 x 20
    Max Slope 45
    Walkable height 2
    Walkable radius 0.1 (I had to set it this low to avoid gaps in the mesh but you get vertical polys with higher values too).
    Step height 1 (increased to try & get RAIN to not leave gaps).
    Cell Size 0.1

    I do not get these problems with the Unity navmesh.

    I’d attach a picture if you had a simple upload mechanism but I guess you don’t really need a picture to know when a poly is vertical!

    I’m using the latest version of RAIN AI from the Unity Asset store, downloaded today.

    Can you let me know the fix (is it a new RAIN version required or something I’m missing here)?



    In case it helps, here’s the setting I used for the Unity generated navmesh which works properly:
    Radius: 0.5
    Height: 2
    Max slope: 45
    - Min Region Area 2
    - Width Inaccuracy 10.71%
    - Height Inaccuracy 4.97%
    - No height mesh



    I’m having the same issues with navmesh on terrain.
    SOmetimes my RAIN navmeshes will not generate at all.
    When they do, I have lots of vertical polys.

    • This reply was modified 1 year, 10 months ago by  bigfiregames.


    If one of you could send us a scene that demonstrates the vertical polys, that would be very helpful. Contact jester at rivaltheory dot com.




    My scene with all the stuff is 1.3Gb and I don’t own the copyright (it’s based on an asset store scene). I will email Jester with the details of the scene, as you suggest. Looking forward to a conclusion as this is early days for me (with this title) & Unity but I am very happy to code my own AI if I need to which is what I’ve been doing since. Hope you can save us some time with what looks like a possibly nice solution.



    If your scene is from the store, just let us know which one. We may already own it.



    Here’s the scene he’s talking about. It’s the “Demo1” scene.

    Here’s the link to the asset store:!/content/10875



    OK, so two issues brought up here, one is with the visualization and one is where navigation meshes won’t even be created.

    For the visualization: It is only a visual anomaly and will have no affect on your actual traversal of the graph. That said it is pretty annoying to deal with and will be fixed in the next version.

    The second problem, where graphs won’t even be generated for a terrain (this is specific to terrain): There is currently an issue in the generation of terrain meshes where we don’t account for the location of the terrain correctly, you should be able to get around this by scaling the Navigation Mesh in the y direction and lowering it (keep the terrain within it, it just needs to include more of the bottom part of the terrain).

    We have fixes for both of these and they should be out in the next release. If this is holding you up though, send an email to and we will see what we can do about getting you a development build (nothing special in it though, just bug fixes).

    Oh, and thanks for reporting these problems. We were unaware of the issues until now and we were able to track them down pretty quickly with what you posted (both bigfiregames and kb).



    Jester, Sigil, Prime,

    Thank you for your rapid response. I’ve some other stuff I can get on with for now. If you can let us know when the fix for the vertical navmesh etc. is in an update and I’ll check it out.

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