Smoothing Groups.

brandoom

(3dmax)

I don't understand them.

I realize they affect the normals of the selected polys. But how do I used them effectively? I dont understand the 1-32 buttons or what their use is.

I'm familiar with maya's process of changing the normal angle. Hopefully this tread isn't too noob. ;]

Thanks

System

Smoothing tries to calculate the topology of your mesh so that light can be distributed across the surfaces predictably, if that makes sense!

Try making a box, adding a single smoothing group to it, see how the object's surface changes in the light. 90 degree bends are too sharp for smoothing to work properly. With that same box add some chamfering and then see the result improve, more edges will result in a better product for lighting.

Specifics are hard to comment on as every model/project has individual requirements but as you get deeper into smoothing you will find areas of a model that require a single group that you want to share with the rest of the model so you join the smoothing groups.

eg;
area 1 : group 1
area 2 : groups 1 and 3
area 3 : group 3

Check this out and do some experiments

Tumerboy

Any polys that are attached to eachother, and under the same smoothing group #, will be smooth.

i.e. if you make a sphere, all faces should be set to 1 smoothing group. If you make a cube, you could use 6 separate smoothing groups to get hard edges between each face.

More efficiently, you could only use 3 smoothing groups, and get the same result, by setting opposite faces to the same smoothing group #.

jocose

EDIT: GAH, two people posted before me, so yeah their answers are probably better.

I know how you feel, really they make no sense to me either. It seams like a way way overly complex way of dealing with something so simple: spliting the vertex normals.

Anyways, how it works is that you can have up to 32 groups. If the entire object is part of one group then the entire model has "soft edges", or in other words all the vertex normals are averaged.

The moment you add some polygons to a group (group 2 ) you will get a hard edges around the border of that group. So basically the edges that defines the border between group 1 & 2 will be hard. If you add another group (group3) then edges that define the border between groups 1, 2, 3 will be hard, and so and so forth.

Really it's just some bizarre concept where you define groups of polygons in order to make edges hard where the groups meet each other. Instead of just selecting edges and saying make "hard or make "soft".

Somebody is probably going to step in here and explain it better than that, but that's my best attempt.

pior

There's also a script out there that let you assign SGs much faster. Basically you select some faces, hit a button, and bam the script 'figures out' what number to give according to what surrounds the faces. It gives you the benefit of working with faces rather than edges, but without the hassle of picking up numbers, EVER. I use it all the time. Will link to it tonight.

Asthane

jocose wrote: »

EDIT: GAH, two people posted before me, so yeah their answers are probably better.

Nah, the first two sounded like explanations from people who use Max, yours is good :P Could be shorter though. "Any edge whose adjacent faces are in different groups, becomes a hard edge" about sums it up

Not gonna comment on the effectiveness of said system, I'm already up to my bitching quota for this month.

brandoom

Thanks for the replies guys! I now have a MUCH better understanding. I'll be using my new found knowledge of SG in the near future.

Thanks again.

MoP

pior wrote: »

There's also a script out there that let you assign SGs much faster. Basically you select some faces, hit a button, and bam the script 'figures out' what number to give according to what surrounds the faces. It gives you the benefit of working with faces rather than edges, but without the hassle of picking up numbers, EVER. I use it all the time. Will link to it tonight.

Wuh? Don't you mean "the benefit of working with edges rather than faces"?
Assigning groups to faces is an oddly backwards workflow, IMHO.

The script I'd recommend is Pier Jansson's Soft/Hard edge script - it basically mimics Maya's behaviour and is much faster than doing smoothing groups the "default max" way:
http://www.scriptspot.com/3ds-max/hard-soft-edge

I hope this is the script Pior was going to link, because if it's not, then I will be very confused!

renderhjs

sometimes images can explain more and quicker:

brandoom

Mop - thanks for the link. I will definitely check it out.

Renderhjs - thanks for the images. I actually stumbled across the poopinmymouth one after posting this thread. But that second one really clarifies what everybody was trying to explain. Thanks

pior

Hehe Mop as a matter of fact I think I tried that one script some time ago and somehow I believe something wasn't quite right about it (but I will double check)

The one script I was talking about really deals with faces, in a very efficient way. Lemme find it (and eventually do a vid about it :P ), I'll post it in a minute

gamedev

... and if you can get away with a mostly unique unwrap, avoid them and set your entire mesh to one smoothing group and bake down from a nice high poly model! **Restrictions may apply, cannot be used or combined with other coupons**