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Login Join Blender StudioSection 4 - Modeling a Game Asset
Chapter 08 - Removing NGons
Sept. 24th, 2015
info License: CC-BY
Francesco Siddi
Publisher
How to use the select tools to easily find NGons and how to resolve them.
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17 comments
Why would you want to remove n-gons?
@ganderson: N-gons may cause issues on deforming meshes. Also if you make the quads/tris yourself, you'll know the exact result when you export the mesh to other engines. If you leave n-gons you're up to the exporter to figure out what to do with those n-gons.
Here Jonathan Williamson explains it well.
@ganderson: Hi, I have just spotted some comments here so I'm hoping that people will still get some insight into things in addition to what Pablo and the info Jonathan Williamson has shared on stack exchange.
This is a good question.
My main reason for getting rid of n-gons at this stage is due to the upcoming uving and baking, both of which can be susceptible to strange artifacts in the bakes or how textures are displayed if the underlying geometry contains N-Gons. In a lot of cases you can ignore this and fix problems where and if you spot them.
However, it is generally good practice to know a reasonable process to convert them into 'cleaner' topology.
Aidy.
I can't find the option to select faces by sides anymore.
@fraznofire308: From Select menu, Select byTrait and it a sub menu. https://www.blender.org/manual/modeling/meshes/selecting/advanced.html
Steve
@fraznofire308: Stephen is absolutely right, this has been moved in the interface. But it's still in the select menu. Open up the select menu, find the 'select by trait' section and you'll find it under there.
Also you can use the spacebar to search, so maybe type in something like 'select by' and it'll have shown up by then. :)
Aidy.
Shouldn't we also remove the n-gons from the hi res model?
@nick.sandow: That's a good exercise, though if the results are fine and it's subdividing as desired, then the bakes should work nicely as a bake source. If I was taking the high poly into a game engine I'd be more inclined to fix those n-gons there to control how the mesh gets triangulated by the target game engine better.
Hope that helps! :) Aidy.
@Aidy_Burrows: Thanks, that does help. When I asked this I really had no idea what baking was, and how the high poly model would be involved in that.
What I realise now is that the hi-poly model is not even exported out from blender - it's only used as an internal reference for generating stuff like normal maps that are applied to the "real", low-poly model. Seems pretty obvious in retrospect. :)
@nick.sandow: you have it exactly! I think baking and all the in's and out's of that could be a complete training course all by itself, we tried to keep the course as short and accessible as possible though! :) Aidy.
does anybody know a script to do that?
@ling talfi: I selected the ngons, then used "Triangulate faces" then "Tris to quads" to clean up the mesh. The result is very close to the manual work in the video.
Doing some reading about NGons I read that Triangles are bad too. Yet we create them in this tutorial with the ALT+P fixing. Should we really be refining the meshes to 4-sided polygons?
*@adamstr* For real-time usually triangles are preferred. Because in the end they get converted to triangles by the graphics card anyway, so we'd be saving them some processing work by making them triangles beforehand.
*@Pablo Vázquez* Ahh ok I see! Thanks Pablo. Appreciate the reply.
There are lots of changes in Blender 2.82. Snapping through Crtl+drag not working with new version. What is the new shortcut of Crtl+drag?
are triangles still valid in 2022? out of all the tutorials i've been thought to make quads over triangles