Theoretical SUB-D

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Old 01 January 2003   #61
I've been using the EPoly->HSDS route to generate high-poly versions of models for normal mapping recently, with fairly good results.

1. You can indeed model at each level of subdivision within the HSDS (although a bit buggy - going back a level occasionally moves a vert or two on the lower level).

2. RE: Skinning at detail level 0 - Haven't tested post-Physique HSDSing since I'm only using the high-poly versions for normal map generation, but I would be surprised if it didn't work

My .02
 
Old 01 January 2003   #62
Sorry to jump in here a bit late.

The n-gon issue:
When modeling vehicles, I use the "solidify" modifier (a dled plugin) to give all my surfaces thickness... I usually apply this after my mesh smooth layer... sometimes 5 sided or other irregular polys create weird artifacts and unsighltly disjoints in the mesh... Also the way the meshsmooth stretches the mesh in those areas can sometimes create lumpy surfaces. I've come to the conclusion that you can get away with it most of the time, but there are some times when you really need to add those edge segments to get better smoothing results....

The method fausto was using seems to create very nice meshes... its usually when you have circular objects all coming into a shared point then you get odd results...

Local Sub-D Issue:
I'm not a fan of this since it really seems to be unstable in terms of being able to go up a level... I've played with HSDS, but found it frusturating and difficult to use for everyday modeling... I do locally refined surfaces by hand or use the sud-d option in EPOLY to add extra detail...

Finally... here are the two images of creating holes in meshes that I posted eairler in the other thread:





U can see that I had to connect edges to control the curvature at the end of the holes... I'd like to do a quick video tutorial on this subject when I get some time...

Comments and feedback please!
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Last edited by Aaron Moore : 01 January 2003 at 07:21 AM.
 
Old 01 January 2003   #63
Adding detail method 2

Useful technique-- most of us know this already, but it might help some of the people who've been asking questions along the way. I know it helped ME a great deal when I came across it, really got me thinking about how to deal with meshes. If you haven't already, be sure to check out David K. Komorowski's website.

This is his way of making creases on an organic model (in this case, a forehead wrinkle). It's part of his
head tutorial.
Attached Images
File Type: jpg crease.jpg (12.8 KB, 2295 views)
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Old 01 January 2003   #64
Good one Gnarly! Thanks!

-3DZ

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Old 01 January 2003   #65
Now..... the question that's been REALLY BUGGING ME. Urgaffel reminded me of it just now with those lovely mech-hip pictures, and mentioning the use of reference objects to snap vertexes to.

The reference objects are all well and good, when the surface you're working on is only curved in one direction-- ie, the curve of the reference object. In the case of Urg's robot-hip, a cylinder. It's easy to make the hole in the hip perfectly circular like the middle of the cylinder, by snapping the vertexes to it. However.... when you move those vertexes, they move in only 2 axes, with no movement according to the cylinder's Z-axis, right? So whatever curve the shape of the hip is supposed to have gets destroyed as soon as we move those vertexes. They have to be CUT in if they're to be in the right spot, and there is no way to MOVE them there. Every time you want to add a detail that involves two curves intersecting, even with reference objects getting the vertexes in the right spot is impossible unless you use booleans, and you can't move anything afterwards.

That make sense?

Okay... now what the heck do we DO about it??
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Old 01 January 2003   #66
Originally posted by Gnarly Cranium
Now..... the question that's been REALLY BUGGING ME. Urgaffel reminded me of it just now with those lovely mech-hip pictures, and mentioning the use of reference objects to snap vertexes to.

The reference objects are all well and good, when the surface you're working on is only curved in one direction-- ie, the curve of the reference object. In the case of Urg's robot-hip, a cylinder. It's easy to make the hole in the hip perfectly circular like the middle of the cylinder, by snapping the vertexes to it. However.... when you move those vertexes, they move in only 2 axes, with no movement according to the cylinder's Z-axis, right? So whatever curve the shape of the hip is supposed to have gets destroyed as soon as we move those vertexes. They have to be CUT in if they're to be in the right spot, and there is no way to MOVE them there. Every time you want to add a detail that involves two curves intersecting, even with reference objects getting the vertexes in the right spot is impossible unless you use booleans, and you can't move anything afterwards.

That make sense?

Okay... now what the heck do we DO about it??


3d snap... I use spline references and then snap my polys to the verts and edges on the splines... using 3d snap I can build a mesh VERY quickly...
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Old 01 January 2003   #67
btw err if the 3d snap isn't working check the snap options and disable the axis constrains... cuz your limiting the movement if that option is on to 2 axis!
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Old 01 January 2003   #68
Aaron any chance of a quick tut of that splinetechnique?
Sounds interesting.
 
Old 01 January 2003   #69
Hey guys

Thank you all for the answer much appreciated.

I think i feel more confident modeling the more i read and get a clear understanding of what or what not to do.

Cheers to a great thread.
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Old 01 January 2003   #70
Originally posted by E.T
Aaron any chance of a quick tut of that splinetechnique?
Sounds interesting.


Trying to get this video recording software to work... the sound keeps going out of sync and dropping out so when i solve that problem... yes i will have a vid-tut
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-Aaron Moore
 
Old 01 January 2003   #71
Something you probably noticed when working with subD modeling workflow is that when you add detail to your mesh by adding edges loops (via selecting an edge ring and then connect) is that an edge loop is drawn but it will flatten out the mesh somewhat. See the picture below to see what I mean.

Ring and connect



Now when this happens the usual thing to do is to perturb the edge loop a bit to regain the curvature. Not too bad if you are doing organic modeling where close enough is good enough. But can be a real chore if things need to be really accurate.

There is no easy way to prevent the flattening out that happens when you add detail using the max subD modeling workflow. Take a look at the picture below showing what happens when you tesselate the same polys.

Tesselate



However, it is possible to use HSDS to insert detail that does not flatten out the curvature. The workflow to do this is rather tedious though. Since you can't easily pass subselections to this modifier and you generally only want to pass it an all quad surface. So it can mean a laborious multi-step procedure involving the detachment of an all-quad surface from a base mesh, an applied hsds modifier, a collapse of the hsds modifier, and a reattachment of the all-quad surface back to the base mesh. But the result is a VERY interesting insertion of detail that accurately retains the curvature.

HSDS



It works, just a real bad workflow, so I don't wind up doing this unless I really need it. If it were real easy to do that would be damn sweet and make the generally strong subD modeling workflow in max that much stronger.

My wish would be that there were some nice easy way to insert mesh detail in max in such a way that the curvature would be precisely maintained. The ideal would be to select an edge ring and then hit connect to add an edge loop exactly where it should be placed to preserve the curvature.

If I am missing something and there is some better way of getting those edge loops to come up exactly where you want them then please share your knowledge. Right now I am thinking that maybe some fancy scripting might provide the way to a better subD modeling workflow in max on this issue.

sam
 
Old 01 January 2003   #72
Originally posted by Aaron Moore
btw err if the 3d snap isn't working check the snap options and disable the axis constrains... cuz your limiting the movement if that option is on to 2 axis!

If 3d snap was on, the vertex would leap way up to the top of the cylinder being used for a guide... it would not automatically rise or fall as much as it should to keep the curve it's lying on consistent. Leaping is bad.
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Old 01 January 2003   #73
Gnarly, you might be able to do it with constrain to edge/face in the epoly rollout, or change the snap from vertex o face/edge. I'm not sure what you're getting at though, so I'm just brainstorming.

Sam: scale the loop along the vertex normals to get the curvature. It will never be PERFECT, but it's a lot faster than detaching and all that.

I've found that using push together with softselections really help when you nede to inflate/deflate an area. For example making a bicep bigger, nose smaller etc. Nose example might not be the best, but you get what I mean I hope.

*Edit*

Gnarly, used a sphere to do the rounded part on your gun. I did use snap to vertex, but could also have checked snap to face I think...

You'll have to elaborate a little more on the cut/boolean thingy...
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Last edited by urgaffel : 01 January 2003 at 10:21 AM.
 
Old 01 January 2003   #74
Sam: good point... err I had a trick for this... will post tomorrow with my method.

Gnarly: There are tons of options for the 3d snap. What are you trying to snap to?

urg: good point on using the scale tool... though I'd half to say that it isn't very accurate...

What about the subdivide tool buit into epoly... anyone play with that?
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-Aaron Moore
 
Old 01 January 2003   #75
Aaron, I did say scale isn't perfect

I was thinking that instead of using hsds to get localized detail, can't you use the subdivide command? I don't have max in front of me, but I feel like thinking that it works like a tesselation. Or am I totally lost?
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