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View Full Version : Please HELP with a simple subpatch problem



chippwalters
09-23-2014, 04:31 PM
Maybe not so simple? I have this curved surface (both ways) (1) and want to insert front and back mic holes (2). But, for the life of me I can't get this to work (3). Any help is much desired!

Here's the file:
http://dl.dropboxusercontent.com/u/3788438/DontMove/subpatchTest.lwo

And a pic showing the problem:
http://dl.dropboxusercontent.com/u/3788438/DontMove/LightwaveSubPatch.png

djwaterman
09-23-2014, 05:40 PM
For a start I would delete the panels you have done and replace them with the original single polygon, and then increase the resolution (poly-count) of the object to give yourself more to work with. I'm amazed you got what you did out of a single polygon face. Why skimp on polygons since it is a detailed section which justifies a heavier mesh?

djwaterman
09-23-2014, 07:02 PM
124453

And object;

124454

chippwalters
09-23-2014, 07:21 PM
It would seem one could do this in less than the patch resolution you show. FWIW, I ended up just freezed and boolean subtracting, but I'd rather have done it in Sub-D. Is the only way to accomplish this by increasing the base mesh resolution? Seems like I've seen car poly cages which are about this rough which have as fine a detail in the meshes.

jeric_synergy
09-23-2014, 07:35 PM
124453

And object;

124454
surely that's wasteful? A lot of those polys are doing very little.

Of course, it's not that it's wasteful per se, all these bits are recycled, but the polyoverkill would make it harder to edit.

(polyoverkill is too much too type: can we standardize on 'POK'?)

djwaterman
09-23-2014, 09:48 PM
It's not wasteful, lose the idea that low poly count is a worthwhile goal for a quality model. Check production quality models and see that they rarely try to cut corners (If you know what the final shape is you wouldn't be editing it after having got the correct shape first, obviously you'd get the overall shape before upping the resolution). It's more important to get a nice looking mesh than trying to be clever or tricky with a low poly count, particularly on non organic product design type objects, there's really nothing to be gained by keeping poly count low, not now days.

jeric_synergy
09-23-2014, 09:55 PM
My concern would be editing this object, that's just a whole lot of points to wrangle.

danielkaiser
09-24-2014, 12:01 AM
Look at your point statistics theres alot going wrong there and it has nothing to do with mesh density.

chippwalters
09-24-2014, 12:53 AM
Hi Daniel,

I always look at the polygon statistics for two and one point polygons. I'm not sure how to correctly interpret point statistics other then if there are single points connected to more than five edges-- it seems like it's a problem. Can you help me to understand what I should be looking for?

meshpig
09-24-2014, 01:54 AM
My concern would be editing this object, that's just a whole lot of points to wrangle.

You can easily strip things back with bandglue and unify. Djw is right, this is a preference issue and even when you want low poly sometimes you get better results by working backwatds.

meshpig
09-24-2014, 02:18 AM
Hi Daniel,

I always look at the polygon statistics for two and one point polygons. I'm not sure how to correctly interpret point statistics other then if there are single points connected to more than five edges-- it seems like it's a problem. Can you help me to understand what I should be looking for?

Single points with more than 5 edges are a problem if the subd mode is "subpatch" and the polygons are five sided. e.g. if you "make pole" an octagonal disc the single point will have an array of 8 triangles around it, no problem

Surrealist.
09-24-2014, 08:25 AM
Here is what is happening:

124462

When it is subpatched it...

124463

An economical "stepped down" version of something that works:

124464

The "dense mesh" argument centers around the trade off between economy and control and a smoother mesh. The denser it is the less movement you will have and in turn less bumpyness due to detail.

It is something you determine on an object by object basis. More organic objects of course have more leeway.

Flat surfaces allow you to step down more steeply

Planned bumps (knuckles on a finger for example) can be a great place to step down.

In general try to be as economical as possible as even with today's computers and ram, things can crawl to a halt with a large scene full of objects.

chippwalters
09-24-2014, 08:34 AM
"Flat surfaces allow you to step down more steeply."
Great advice.

Thanks Richard! Exactly what I was looking for! Can you post the UN sub-patched (Tab off) version of those images? Just so I can see exactly how the topology looks? Also, were you able to view this in specular shaded mode to see if there were any surface aberrations or wrinkles? Even if there were, I suspect by fine-tuning the Z values of the coordinates it could be made smooth, though it may take a bit of time.

Much appreciated!

jeric_synergy
09-24-2014, 08:47 AM
2nd on the "unTabbed" (ie polygonal) request: I hang my head, but it's just so much easier to understand in poly mode. :question:

I'm always stunned by Richard and JoePoe's ability to simplify a subd hairball. Wizards!

Surrealist.
09-24-2014, 10:31 AM
124465

Yeah I usually do that, but forgot.

I always work with subpatches turned off for what it is worth.

And this mesh is a mess. I mean if you were looking for a hard surface smooth mesh you could subdivide it more first. (so you would not have to step down) I just wanted to show the basic poly flow.

PS: Not a big fan of endless tweaking on a mesh that has been stepped down. Do it a little but if it is causing issues give yourself more geometry.

chippwalters
09-24-2014, 10:39 AM
Would you use metaform to step down and keep the original 'form' or would you just do a regular subdivide? Thanks again for your help!! Much learned from this thread, in particular, when working with hard surfaces, start with more geometry than the minimum necessary to define the shape.

jeric_synergy
09-24-2014, 10:52 AM
I think the impulse is the to keep the object "regular" or "even", but if it makes more sense to have a bunch of subdivision that extends all the way around (i.e. no stepdowns), I'd like to hear that too.

That would certainly be easier than the network of stepdowns, plus a lot fewer points/polys than a uniformly even distribution of division (album name).

JoePoe
09-24-2014, 11:33 AM
First of all, THANKS Jeric for the kind words. I'm just happy to be mentioned in the same sentence as Richard. :)


At this point, this is just a mental exercise right?!
I certainly vote for more general geometry to start.

**I don't recommend this :D**..... :hey:

So...I was able to get it down in a hurry... If you don't mind a few (6) triangles (edit: heck, you can get rid of those pretty quick now that I think about it). Only required two extra vertical cuts and one horizontal in the original object. The 5 stars (there are a bunch.... but nothing over) seem to be behaving themselves for the most part (as Richard says, that's easier done the flatter the surface)... even considering that I built the piece off site and patched it in..... It's a flat piece patched into the curved/off axis surface. I'm sure the angle of connection is not perfect.

124467 ...... tightened a little 124470

124468

Green is the only addition to base mesh.

124469

Edit: (oops, forgot nudge the corner radius back into shape. The horizontal cut tightened the corner radius a bit. Easy fix.)

Edit 2: trust me, it's easier to see what's going on SubD. Things are just packed in really tight. 124472

XswampyX
09-24-2014, 01:11 PM
Here's mine...

http://i465.photobucket.com/albums/rr16/xXswampyXx/Simple_SP_zpsf3e5942e.jpg (http://s465.photobucket.com/user/xXswampyXx/media/Simple_SP_zpsf3e5942e.jpg.html)

You can't make them square with the number of polys you had. :(

JoePoe
09-24-2014, 01:22 PM
Hey Swamp!

Did you find that adding in six cuts (or so) messed with the smoothness of the rest of the low poly object surface?
Gave me some pretty noticeable faceting. Especially with the high gloss.

XswampyX
09-24-2014, 01:27 PM
Yep, a little bit, but if the object had a few more polys before the holes were put in then I don't think it would show.

Good call mind!

I think just UV'ing it and then making a transparency map/image would be the best & quickest thing.

Surrealist.
09-24-2014, 08:30 PM
Would you use metaform to step down and keep the original 'form' or would you just do a regular subdivide? Thanks again for your help!! Much learned from this thread, in particular, when working with hard surfaces, start with more geometry than the minimum necessary to define the shape.

I put a definition of "stepping down" here:

http://www.lightwiki.com/wiki/Fundamentals_of_Subpatch_Modeling


Stepping down

Stepping down is the process of taking your high detail areas and reducing the polys so that the over all mesh area is less dense. And again in doing so you create more 5 poly points and, depending on your method, perhaps triangles.

With some illustrations and explanations.

And on this page I talk about adding detail to a curved surface.

I explore the various problems you encounter with a lower poly mesh to start with and how starting with a higher density mesh solves some of the bumping issues:

http://www.lightwiki.com/wiki/Fundamentals_of_Subpatch_Modeling_Part_Five

8 sided disc:

124476

16 sided Disc:

124477

If you do this tutorial from start to finish you have a real good grasp on what is happening with SubD and how to solve most of the issues you will ever encounter.

And as you have seen so far, here are a lot of guys here that are extremely clever with SubD. So no shortage of help if you ever get into a pinch.

But these things so far are just the very basics and they are fairly simple. :)

chippwalters
09-24-2014, 09:05 PM
I think the impulse is the to keep the object "regular" or "even", but if it makes more sense to have a bunch of subdivision that extends all the way around (i.e. no stepdowns), I'd like to hear that too.

That would certainly be easier than the network of stepdowns, plus a lot fewer points/polys than a uniformly even distribution of division (album name).

Awesome, Joe. You guys are such a big HELP and INSPIRATION!!! Thanks so very much :)

- - - Updated - - -


Yep, a little bit, but if the object had a few more polys before the holes were put in then I don't think it would show.

Good call mind!

I think just UV'ing it and then making a transparency map/image would be the best & quickest thing.

Yep, except Keyshot doesn't do transparency maps. I ended up do a boolean after the mesh freeze, but this is what I really wanted. Plus, I want to be able to print this out on my Affinia one day. Thanks again!

chippwalters
09-24-2014, 09:08 PM
Yep, a little bit, but if the object had a few more polys before the holes were put in then I don't think it would show.

Good call mind!

I think just UV'ing it and then making a transparency map/image would be the best & quickest thing.


Richard, I would have been completely LOST without your tutes on Polyflow. I've been knocking my head against box modeling for years now, and never really put the time in to learn how to do it correctly. This is primarily due to lack of decent tutorials or an understanding of concepts like Polyflow. You've really done a great service to this community with your tutorial!