Bevel vs Bevel Modifier

(Mods, please feel free to move this if you think it’s in the wrong section)

I am building a scene and there are a lot of bevels to get rid of the old “hard edge” issue. It lead me to thinking if there is a performance / memory difference between “hard bevelling” the actual geometry, or using multiple bevel modifiers with vertex groups / edge weights.

Has anyone any information on this? Obviously using modifers means the bevels are dynamic and so there is flexibility to modify geometry easier. As to UV’s, I’m not sure how the modifier actually handles that.

With having a lrge number of items, I’m just wondering which is most efficient, or is there no measurable variation in terms of rendering / processing etc?

Even if it’s not the same code (it may well be), they both produce a comparable amount of geometry. I wouldn’t worry about it.

If you use Cycles, you should check out the upcoming shader-based bevel in this (misleadingly titled) thread.

I am usually in favor of non destructive solutions. But in this case I think you might want to explore not using Bevel or the Bevel Modifier. Edge smoothing is not handled as well using Bevel as it is using other methods. I am not at the computer now. But I could put together a few examples of techniques later.

I Think this should be moved to Modelimg support.

Moved from “General Forums > Blender and CG Discussions” to “Support > Modeling”

I look forward to it. I am talking hard edged modelling here, (buildings, street furniture etc…) and so just assumed you either used the modifier or bevel tool. Always open to new ideas to put in the old noggin. :slight_smile:

Sure. Sorry it has been a busy last two days at work. I will try to put something together today.

Double post.

The code is the same for the bevel tool and the bevel modifier.
The modifier method will introduce a performance penalty for viewing end editing the model, because the code reruns fairly often, and each time it has to convert a derived mesh into bmesh, which is not super cheap. Plus you are talking about a stack of bevel modifiers, each of which has to do that.
But unless your mesh object is quite large and the number of beveled edges is also quite large, I bet you won’t notice the difference, so you shouldn’t worry about it until you feel viewport performance is laggy and you want to try to do something about it.

If you are talking about a rendering performance difference – I don’t know for sure. I suspect there is also a performance difference there too if animating, but maybe the final mesh is calculated only once and cached.

The good thing about modifiers is you can turn them off while doing other stuff.

OK. As promised.

For starters you have the "Auto Smooth: setting. This would basically be the same as LightWave smoothing angle.

The Problem with the bevel tool is that, say you start out with a smooth box:

You can see of course the smoothing errors. When you ad the bevel modifier it really does not fully handle the situation completely.

The reason is because of how the smoothing is calculated. Edge to edge.

another auto smooth example:

Because Smoothing is edge to edge:

One solution is to add more geometry:

And you get a smoothed edge result. There are other solutions.

There is also the edge split modifier for some situations.

It was a bit of a rush writing that on the train. But essentially what I am trying to say is if even if you have several segments on the Bevel it will still calculate smoothing to the next far away edge. And you could also try that along with auto smooth.

But I find that it is better to just work out adding geometry by hand.

Maybe you use more than one technique on a model.

Bevel modifier doesn’t have a limit set by default which isn’t helpful. Bevel tool gets its limit from the selection but adding bevel modifier in the stack means first beveling everything. Angle limit would be a better default, like it is with auto smooth and edge split, because

  • it generates less geometry in the viewport
  • it usually needs to be limited with something when it goes in the stack with other modifiers
  • if the geometry has high angle edges that needs beveling, angle limit would affect those anyway

Yeah, I use auto-smoothing a LOT, it was the thing I didn’t know in Blender when first moving from LW and missed it terribly, (not knowing it actually existed :wink: ). I think it’s one of those features so often overlooked.

Thanks Howard, very useful info. :slight_smile:

Running win8.1 Blender 279.1 - Is anyone experiencing this? I add a new cube, Tab in to edit, select edge, Ctrl+B, works fine. Back out of edit. Back into edit, select new edge, Ctrl+B and it freaks out or it doesn’t work at all. I have to restart blender between each bevel.

check the new builds, as that error is already fixed.

thank you, will do.