Retain creases after applying subdiv modifier?


I’ve been slowly picking up Blender for a while now and I am new to the forum so please forgive me if I am posting this in the wrong thread.

I’ve actually got a ton of questions but I’ll stick to this basic subject for now.

I’ve got a model with creased edges and a subdiv modifier. When I apply the subdiv modifier (and any other modifiers on the model at the time) I lose my creasing information.

  1. Is there a way of subdividing the model WITHOUT using the modifiers and so that it respects the creasing information, too?

  2. Is there a way for the creased edge information to be stored before subdivision that does not use vertex groups?

Usually, I want to create a very low poly model with creased edges which I would then subdivide, make minor mesh modifications and apply beveling to the creased edges. The edges were pretty much 100% creased so there were no issues with weighting variations. Since I came from a Lightwave background, I had already had my own modeling ‘rhythm’ and process specifically in using ‘surfaces’ to denote where my creasing border was meant to be (creased edges or ‘edge weighting’ is seriously broken in LW) but until I can find a solid workflow to make up for my translation to Blender then I will have a frustrating time modeling in they way I want to model.

So, if anyone can help in answering my questions then I’d be grateful.

Thank you in advance.

Paul :stuck_out_tongue:

I don’t think there is a way to keep the creasing information on an object that has had it’s subdivision surface applied. This info is only used for subdivision surface based modifiers, so blender assumes you don’t need the info anymore when you apply the modifier. They’d probably also have to apply the creasing info to the new geometry, so its more work for them to do to support instead of some simple change like setting it to not throw that data away.

Whats wrong with using vertex groups for this? Also, why not try working without applying any modifiers. The bevel weight attribute seems to work in 2.8, so you can just keep the subdiv modifier on and set the bevel modifier to use weight.

If you need to sculpt detail into the subdivided model, then use the multires modifier instead of the standard subdiv. With the multires, you sculpt on the new geometry created by the modifier; in the standard one you are just moving the original verts.

Edit: I just realized that 2.8 does keep edge crease info after you apply the modifier. See if you can use the workflow you want in 2.8.

I think it would be good to provide more information about what you are trying to do with regard to the edges. And your overall target. I mean are you rendering in Blender or exporting to a game or rendering in LightWave? In LightWave you can weigh each surface with the smoothing option on/off and values. You can’t really do that in Blender in the same way. But you can use Auto Smooth and adjust the angle on an object by object basis. (mesh tab) Similar to LightWave smooth option by Surface. But I think it would be good to step back and describe your objects more and what you plan to do with them.

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Edit: I agree with @Richard_Culver, it would be good to provide a bit more information about what you are trying to do. Perhaps a couple of screen shots of this issue you are having/trying to solve would help.

Original Reply: I am very new to Blender but, when I need to keep a well defined edge or crease when applying the subdivision modifier, I usually add an additional edge loop to either side of the edge that I want to stay defined.

This is what happens to a cube when applying sub-d.

Now if we add a couple edge loops near the upper left edge of the cube.

And then apply subdivision again, it now has a much more defined edge crease on the top left edge.


Sorry if this is not what you are asking or if it’s not the best way to acheive this, but that is what I’ve been doing as I am modeling and learning Blender.

I hope that helps some.

Happy modeling.

  1. In Blender, Crease Weight is an information that only takes sense when a Subdivision Surface modifier is added to the model.
    In Edit mode , a Subdivide operator exists and it has a Smoothness setting.
    You can press Apply button of modifier. As a result, original mesh becomes subdivided and object has no more modifier.
    So, you can consider using a Subdivision modifier as a temporary modeling step and not as something permanent.
    Subdivision Surface modifier is by default using a Catmull-Clark method but another one exists. Simple method is subdividing the mesh without modifying angles between faces. That is a lot more simpler than creasing all edges of model.

  2. I don’t know from where comes this misinformation, misunderstanding.
    Creased Edge information is stored before subdivision and it does not imply vertex groups.
    Crease Weight is a property of the edge. By default, this weight is set to 0.
    But if you change this weight for one edge to another value, this value is kept while modifying the edge until you reset it.
    If you subdivide or extrude the edge in edit mode, resulting new edges inherit same Crease Weight value.

It sounded like he wanted to use edge creases as a way of quickly selecting certain edges that he wants to bevel after he applys the subdivision surface modifier. I don’t think he thinks edge creases have anything to do with vertex groups. He was just asking if there was a way to reselect those edges without using vertex groups.

I was just wondering why he doesn’t want to use vertex groups for this same purpose.

You are right.
It is not an obvious workflow that for selecting elements by a shared property, user have to select one of them and use Select Similar (shift G).

Thanks for everybody that replied. My Lightwave workflow was purely for Lightwave only. I’m learning and using Blender (2.79) because my new OS is Linux and LW is not an option (LW via Wine is horrible). I only have a new laptop and want to stick to an OS that is not evil bloatware (IE Win10).

Basically, I want to be able to work in the most lowest resolution as possible with creases (for hard surface modeling), have the subdiv modifier as reference for how the final model will look then apply a medium level resolution subdiv and add bevels later using the creasing info as reference.
You see, if I were to add the edgeloops at the lowest level of the model and apply the subdivisions then the final result will have lots of tiny extra polygons that are just unnecessary. Cleaning up afterwards is just a time consuming pain this way.
By using my workflow, I don’t have those extra unnecessary polygons.

The result is a decent medium level model that I can sell that will render decently with and without subdivisions depending on the needs of the purchaser. Trimming unnecessary polygons is highly important when creating models for sale in the same way that good topology is necessary for proper animation.

I’m glad that 2.8 retains the edges, though. I’m still working (and learning) in 2.79 so I suppose that I will have to swap versions when I need to do the subdividing before beveling the creased edges.

Oh and as to why not use vertex groups, well, when I save edges as a vertex groups, especially on a low level model, what I get when I bring the selection back is basically a vertex selection instead which includes ALL the adjoining edges and not just the ones I had selected.

Thanks everyone for the feedback and help. I appreciate all those who contributed.

Paul :stuck_out_tongue:

In that case you really should use the multires modifier instead of a normal subdivision surface. It is based around having adjustable levels of detail. You start with a simple base mesh, subdivide as many times as you need to using the multires, Sculpt detail on the highest layer, then finally you can set it to one of the lower layers and apply the modifier to get something with less detail that conforms to the outline of the high detail layer (set it by changing the “preview” setting to something like 2 or 3 before hitting apply).

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It is looking like it is going to be a job of going back by hand to do the selections to make a bevel. Something that might help will be in the select menu “Select/Sharp Edges”. This will probably do better than 80% of that work for you. At least on a case by case basis. It could wind up saving a lot of time. :slight_smile:

Yeah, but since I also have 2.8 installed, too, and the creases stay after applying subdivs in that version then it isn’t a problem any more becuase I can jump versions when I need to do the final edge beveling.

Still, I am grateful for all the tips.

Paul :stuck_out_tongue: