CGTalk - smooth to sharp edge transition, Darth Vader mask, 3dsMAX

View Full Version : smooth to sharp edge transition, Darth Vader mask, 3dsMAX

Phelonius

03-01-2005, 10:11 AM

Hi All,

noob and first time poster here so hope i get it right ;-)

I am new to 3dMAX and have given myself a few learning projects to try to get my head

around it a little. One of the things i picked to start off the top of my head was

the Darth Vader mask from star wars since it has a pretty good range of features to

try poly modeling on.

However, Im running into a big problem and dont know if its my workflow, or if there

are some tricks i can use to get this right.

In the pic below you can see that the 'mouth' area is the issue im struggling with.

This should be completely angular with sharp edges (pic 1), whereas the rest of the

piece is smooth, or has slightly more rounded/filleted edges. Now, this is all one

piece and Ive poly modeled it. I have tried a few things and this is where Im

getting frustrated.

If i try to put in detail at the 0 level around the mouth, ie chamfering slightly all

of those edges, there are all sorts of horrible things that happen, ie lots of

irregular ngons and tris forming etc and it obviously looks horrid when using NURMS

output. It actually looks similar to just using a NURMS output whilst leaving all

those edges alone (pic 2).

One approach I have tried is using MSmooth on all the faces except the mouth part,

and then using NURMS level 1 (see pic 3) which does ok except for the incorrect

shading on the bits of the mouth that are supposed to be planar. I am aware that

this is because its a many-sided nGon in effect, because of the geometry there, but

tesselating it, or breaking it up more creates the problem in pic 4, that is, all of

those faces must remain planar to each other.

I have struggled for hours with this going around in great detail trying to doctor

each face/edge etc, but I think that is really sloppy and I want to get off on the

right foot here. Can anyone suggest some tips for me?

I thought that there should be some way to do it as a separate piece and then connect

it seamlessly to the main mask assembly, but once again, I got into the problem of

taking a smooth surface, and trying to neatly terminate detail into a very planar one

and it didnt work out neatly....

Any recommendations are most appreciated!

Cheers,
Phelonius

http://home.planet.nl/%7Epauls064/help.jpg

BlackL1ghtn1ng

03-01-2005, 11:52 PM

when you are making your polys, make sure to assign smoothing groups to them. Then when you use mesh smooth, make sure 'use smoothing groups' is checked. That way, when you smooth it all polys that don't have the same number assigned to them will not blend together and you'll have your sharp edges and smooth edges all in one object.

gjpetch

03-02-2005, 02:02 AM

Try a three edge (AKA solid) bevel.
http://www.3dluvr.com/content/article/149

Depending on your topology, you would either achieve this with bevel, connect, cut, or the extrude edge tool with hieght set to zero.

I always find turning on edge constraint in editable poly is useful when doing this kind of stuff, so that you can move around geometry without disturbing the shape of the model.

Phelonius

03-02-2005, 11:39 AM

Thanks for the input guys,

BL, I had been working with smoothing groups but firstly, the smoothing over the surfaces doesnt solve the problems of the ngons on the large, flat places. These still shade incorrectly due to the triangulation of the ngons, and after all, at render, its dealing with all those acute tri's that make up the ngons. Secondly, i actually DO want to smooth this if possible, just with very hard edges. That means i sort of have to put in my detail at the 0 level in this case and then move to higher detail. Which brings me to gjpetch's technique...

Its quite funny that actually i played with the edge extrusion at 0 height (only a base value) and it did pretty good. There are still some screwups though because of the basic topology there, but the edge constraint thing i didnt know about, great tip! Looking back, i dont think i could have possibly guessed that there would be any difficulty doing the vader mask in an hour or so, and now im beginning to laugh at that idea :-S its actually quite a good exercise to do it as a one piece poly!

Just wish there were decent booleans for this sort of stuff...

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