Smoothing & Tessellate
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Smoothing & Tessellate

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I. Smoothing

Q. I've noticed that NWN MDL's are pre-smoothed when imported into max using scooters plug-ins. Does the game support smoothing ? I've tried experimenting but haven't noticed any difference in smoothed and non-smoothed models, although I'm not sure whether I'm missing something obvious -Martin E

A. To get smoothing you need to select faces and set smoothing groups. The engine does support smoothing and that's how you set it or unset it as the case may be depending on what your needs are. -Danmar

*Always weld your vertices first. You'll save yourself some agravation. -DoA

FAQ from Torlock

As some of you know, there is a smoothing mask in all the faces in ASCII model files. This is the 4th parameter in the "faces" definition. How it works is that for every vertex in a face, if two faces share that vertex and the ANDing of their smoothing masks yields a non-zero value, then the face will contribute to the vertex's normal.

The important think to note is that *IF* more than one bit is set in the smoothing mask for a given face, then that face can contribute to the vertex normals of multiple smoothing sets.

3DSMax: You can use the Smooth modifier to auto-smooth an object. Smooth parameters include options for Auto Smooth and Prevent Indirect Smoothing along with a Threshold value. The Parameters rollout also includes a set of 32 Smoothing Groups buttons labeled 1 through
32. These same Smoothing Groups are available as options for the Polygon and Element
subobjects.
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Danmar

Smoothing issue.
Image

The sides and top are all in the same smoothing group and as a result the engine is trying to approximate a spherical surface flowing over the edge with shading. This causes them to be fairly obviously tiles.

Select the Object. Go into Face mode. Do a Select All to select all the faces.

Scroll down in the rollout until you find the Smoothing Groups section. Click the Clear All button.

You could also try an Auto Smooth with the default 45 degree angle.

As part of my tiletools (Most of which is meaningless for a non-studio max+mdlsuite user) there is a smoothing tool which lets you select any number of objects at once and do an auto smooth on them of a specific angle. Should be on my site somewhere.

This comes in _extremely_ handy for imported objects. Neither NWMax or MDLSuite honor smoothing groups so anything imported in those is set to a single smoothing group.

There are countless objects and tiles out there in haks that have the the telltale signs of this. They look a little 'puffy' or rounded over on the edges with no sharp demarcation lines. When you import an item into Max the import tools stick everything into the same smoothing group. If you look at many modified tiles released to the public in the toolset you'll see rounded looking corners that should be 90 degrees. This is because they were saved as a single smoothing group so the client tries to smoothly shade across every face.

For me its fairly simple, I apply/run the tool against every tile I import if there are any square edges on any object in the tile.

The easiest way to see the problem is to import any tile from the city interior or exterior that includes a wall of some kind. Export it without making any changes. Stick the export in your override and open the toolset and paint that tile down in an area. The walls will have a rounded over look to them at the edges where the engine is trying to smooth the shading normals over to approximate a curved surface.

THe reason you don't see the errors a significant number of times more often than you do now is the construction method of the tiles where the various edges that make up an angle are actually separate objects and thus aren't smoothed over.

You see it most in the city interior tiles on the walls+top which are a single object and any pillars/posts/supports in the tile itself.

The default angle works well for most things. Things that are supposed to be straight edged will be and things that are supposed to be smoothed over are.

Where you'll run into exceptions is, off the top of my head, a couple of the city exterior tiles have some facected stonework that the builder created as faceted, at least the original tiles are, that end up smoothed. Unless you import/export all of them the mix of smooth versus faceted looks out of place.

Thin flat items like sword/blade parts especially though desperatly need this done to them as they look tons better.

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Post by Guest »

II. Tesslate

Q. I'm modelling a tower on a craggy rocky outcrop. I've done the base model but need to add more 'sculpted' detail to the rocks. Is TESSELLATE the best way to add polys to the mesh, or is there a better way that doesn't send the polycount through the roof ? I'm still fairly new to modelling with max in this way. -Martin E.

A. Tessellate is probably the easiest way to do it. You can manually divide edges but its a pain in the ***.

And you can change the type of tesselation and the amount of tesselation to avoid that monster poly count. You can also apply (like most) the tesselate modifier to a subselection of faces so you only add extra faces where you need them. -Danmar

A. I`m working on a new caverns tileset and I use tessellate very often. I first create the basic structure (outer edges, general form) , with very few polygons. Then tesselate to get the more natural look, and smooth afterwards. All in all it looks quite "rocky". -Velmar

3DSMax: You use the Tessellate modifier to subdivide the selected faces for higher-resolution models. You can apply tessellation to either Triangle or Polygonal faces. The Edge option creates new faces by dividing the face from the face center to the middle of the edges. The Face-Center
option divides each face from the face center to the corners of the face. The Tension setting determines whether the faces are convex or concave. The Iterations setting is the number of times the modifier is applied.

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Christopher
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More info on Smoothing...

Post by Christopher »

I found this tutorial on smoothing to be useful. I have been Goggle searching the subject as I am currently working on a CTP Desert City tileset. The issue of importing mdl's and having the import tools stick everything into the same smoothing group is a pain.

Good Link: 3dsMax Smoothing Groups

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Bannor Bloodfist
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Post by Bannor Bloodfist »

Grabbed this post of Bannor's to share some good information

The settings for smoothing are a cutoff point. the number you select is the 'angle' that is used to determine smoothing. a number of 45 is 45 degrees and would NOT SMOOTH a 90 degree corner, but anything LESS THAN or EQUAL to 45 would get smoothed... like barrels.

Building corners are typically 85-95 degrees.

Smoothing works on a face by face algorithm. Not a problem with high poly models, but with the severely low poly models that NWN uses, it can cause those ball shaped 2nd story blocks on buildings. The reason this occurs, is a face only has 3 sides, and smoothing affects the edges of that face. If a building has two faces to cover the entire section... like 90% of the buildings in this set, then smoothing this with a 90 degree setting will cause the lighting on the texture to smooth both the right hand edge AND either the top or bottom edge.

Notes:

More polys between outer edges, means a much smaller difference between each individual edge between faces. This allows for a MUCH smoother transition. Most NWN tile mdls, have been 'reduced' in poly counts, thinking that this would make things load faster.... this limits us in the amount of real smoothing we can get.

If you look at the 4th pic here, the brown building, and pay special attention to the TOP section, you can see how bad a 90 degree smoothing looks when you only have two faces per object side. It actually causes a hard edge between the two faces that you can not remove unless you change the smoothing. It also causes that darkened edge on the two outside edges of this particular mdl. This building looks TERRIBLE in game with 90 degree smoothing. 85 degree works ok, but really does NOT smooth those corners at all as they are 90 degrees. Since we only have two faces per side of the boxes here, there really is not much we can do. This building will ALWAYS have a hard edge on the corners OR will look like that particular shot does now. Which to me, is not acceptable.

Nothing can really be done about this, except to have the objects have their poly counts increased.

That is not something that I am willing to attempt at this stage with this set.

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