are ngons a good or bad idea?

are they something that should be used only when it can’t be avoided?
I was under the impression that the best thing was to have squares. Triangle ok only if object not moving.
thx
D

In my little experience Ngons should be avoided in organic objects in general, where it’s preferable to decide for yourself where edges should be; in particular, if the object has a subsurf modifier, all faces should be squares.

In many other cases where there are flat surfaces, I think they are harmless, just be careful with concave ngons, like ‘C’ shaped faces, but you have already experienced this issue IIRC.

paolo

Not good at all if you want to sub-d. eg: organic objects, cars, aircraft, etc.
Good for flat surface. eg: house wall, ceiling, floor, lowpoly object, etc.

ngons are to be avoided mostly for topology control reasons. blenders edge tools will stop when they hit an Ngon. edge select and loop cut can be rendered useless this way later in the modeling process by careless use of ngons and triangles.

the other good reason to avoid N-gons is if you plan to export the model into a game engine or other application that might not know how to handle an N-sided polygon, and will then give you holes in your mesh or just flat refuse to open it. meaning if you want to share/sell your models, stick to quads!

but if your staying in blender. just rendering still images. you can use them where ever you like. just be prepared to explain your reasoning when people see your wireframe and question your modeling skill! haha

I think we should divide into the final result and workflow / tool needs.

Nobody wants N-gons in the final mesh really. Not when you can avoid it. N-Gons can introduce odd shading, they kill edgeloops and the mesh flow as mentioned by Dave_K. They make problem with animation and wrong deformings, and they make trouble with subdivision surface. So even in Blender you better end in a clean quad topology. You can leave them where they don’t disturb though. They are not evil per se. Same goes for Tris.

On the other hand, N-gons are essential for workflow. And they are essential for some tools. Knife tool does not work without N-gons. Gone the days where you were unable to reconnect an edgeloop because Blender triangulated immediately in the way …

Ngons are your best friends for modeling architectural flat things like houses or making 3d-print models (stl-format will triangulate ngons anyways and doesnt care your smooth/flat -shadings, its always real geometry, flat shading).

ngons and tris are something more final. Quads are good for when you are still building/expanding the model.
Then once you’re happy with the shape you can simplify or clean it up by adding ngons or by using the decimate modifier.

It’s really up to you and what your scene is requiring. Static objets that never move such as environments, it really doesn’t matter.

When you’re new I think sticking to quads is the best cause you will be learning the core of modeling by using them.

Thank you all
(Note to self avoid ngons, amap)
I only had one recent brief experience with them. And din’t like it very much, although i am sure have had ngons in the past just due to plain bad modeling.
Iwas checking out the most recent tutorial from blender cookie and ngons were used. which perplexed me a bit as it thought it would have been better to avoid them.
You all have a great weekend.
D

To be clear, you don’t have to avoid them while modeling. Modeling is the reason support for n-gons was included in the first place. Just final model is where they’re either considered bad or are ok, depending on requirements and the purpose of the model. Most often bad because of the deformation/shading/unwrapping issues.

It’s sometimes bad to have quads too. For example, if you’re baking a normal map for game engine use and don’t triangulate the model before baking, the triangulation might change after baking and that might cause artifacts in the final. A quad has two triangulation options. An n-gon has several.

Ngons are a step along the way.

all good advice, thank you all.
D