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View Full Version : Subpatch curving in corner of polygon



Bangalow
09-19-2007, 06:06 AM
Having bought Dan Ablan's Lightwave 8 to demystify the process of 3d modelling, I thought I would model a computer mouse (just for fun).

Having set up the splines, I seem to be having problems subpatching as I am always getting these 'holes' in the corners of the polygons. How does one prevent this from happening so that as the patching takes place, the polygon edges meet (to make a mouse without weird triangular holes).

I've have read the manual and while the tutorials in the book don't seem to give this problem, however on my own modelling of a simple object, I get this problem.

Any help would be greatly valued. :help:

BeeVee
09-19-2007, 06:12 AM
You need to merge points since you have two separate subpatches there.

B

dwburman
09-19-2007, 07:52 AM
Should the two meshes have the same number of divisions so the points all line up?

Surrealist.
09-19-2007, 11:28 AM
Also looks as if you had accidentally used bevel or extender plus on those top polygons. If you press Tab to turn off subpatches I would guess that that beveled pattern would go away and with subpatches on it reappears. To fix it merge those polys with subpaches on and delete or merge the extra points.

The corners will always do that when you have a grid subpatched. Connect them like Been says and make sure you make the same number of segments like dwburman pointed out so that they can connect.

To make spline patching work you have to make sure that you always use the correct amount of segments.

Personally I don't really recommend spline patching as a starting point for subpatch modeling. It is actually a technique best used for other purposes.

However I do think learning spline patching is a valid tool for a modeler so I don't want to discourage it. Do understand that it is a technique that was developed before we had subpatches. There are better techniques that cater to the "rules" of subpatching if that is the way you want to go.

Bangalow
09-20-2007, 03:12 AM
Thanks for the replies people. What an excellent, helpful forum.

Beevee - Merge points? I will start looking into this. Trying to master Lightwave so will do some more reading on this.

dwburman - Yeah. I thought the different number of polys may have been the problem, but the strange rounded corners appeared when I patched the area with the same number as its neighbouring spline area.

Surrealist - Lots to think about here.
Basically I have photographed my computer mouse from top, side, front and thought using splines would be an accurate way of tackling the project (as opposed to box modelling).

I really have no preference to how to do it, just whatever method that I can understand how to do, and leaves me with an ultra-realistic model of the original.

Looks like I had better look into merging points - not sure how to do this but will experiment some more. Bit of a beginnner but I really want to get a better mastery of techniques and processes so modelling isn't fraught with stumbling blocks.

Thanks for your thoughts - now to try these ideas out.

Bangalow
09-20-2007, 05:03 AM
Well, I always think I have reasonable intelligence until I spend time in Lightwave Modeller. :thumbsdow

Could one of you please post back with a few quick steps outlining which points to merge so I can move forward with my project?

Thank you. :) :)

Bangalow
09-20-2007, 05:39 AM
OK. I seem to have gotten there by sheer fluke.

Talk about a trying experience. There seems to be a large gap (for me at least) between learning how to do things and the wonderful work that other people are able to produce (and the jargon that goes with that).

Thank God for NTs Discussion Forums.:) :)

Thank you again Beevee, dwburman and Surrealist!!

Surrealist.
09-20-2007, 10:17 PM
Merge points is m. In the dialog box you can choose the maximum distance.

Or you can pick each pair one at a time and weld ctl w

Merge polys is select two or more then Shift z

A great place to get a handle on a lot of the basic LW tools is in my signature (Suture.net)

This should get you up and running. Then if you take a look at and go through the steps of my tutorial you will come out the other end knowing quite a bit about modeling with subpatches.

Bangalow
09-21-2007, 12:29 AM
Thank you Surrealist. I will check out the tutorial.

As it happens, I solved my problem for one section of subpatches, but the problem exists for other areas of subpatches - which I can't seem to solve.

Short of wrapping the mouse in glad wrap, placing dots all over it and photographing this and doing point to point modelling into polys, I am keen to keep trying the spline modelling method as the curves are real accurate from the photographs.

Really having trouble working out what points I need to merge but I will check your tutorial out - I am sure this will help.

Thank you.

Bangalow
09-21-2007, 03:19 AM
Hi again

Still not really sure how to eliminate the little holes between patches. Have read the tutorials - still perplexed.

Also the attached render has small 'seams' that are occuring between the sections of my patching. Is there a smooth function (other than Surface Editor smoothing) that can elimenate this problem in Lightwave?? I know there is smooth curves but this is more of a smooth between polygons either side of the spline curve - what can get rid of this slight change in mesh at this point?

Could anyone please give a few numbered steps I should follow? I've searched high and low so far and can't solve these.

Thanks in advance anyone...:)

Bangalow
09-21-2007, 03:34 AM
OK. I think using a 20x20 mesh on the subpatches has resulted in such a smoothness of subpatched polys that the seam between these sections shows up as a shaded line on the surface. I'm guessing decreasing the resolution of the mesh of both parts would make this 'seam' a little less obvious.

Crazy that I am answering my own posts - the effects of working too long on this problem perhaps...

Surrealist.
09-21-2007, 03:35 PM
The seem you are experiencing is most likely because your sections are not connected. You can see the corners are not connected it yet.

In wireframe mode, subpatches turned off, go through and select each point(s) along the seam and make sure there is only one. Then if there are two use the weld (shiftw) command. Do this with all the points along the seams. Then make sure they have the same surface name (q) and have the same smoothness settings in the surface panel (on or off basically, you can leave the smoothing angle to it's default for now.)

If every thing is connected and the same surface AND you don't have any 2 point polys (w for statics panel in polygon select mode) all should be smooth.

Bangalow
09-21-2007, 08:33 PM
Hi Surrealist,

Thanks so much for replying. Your constant posts to my mouse problem are very encouraging to me. I believe I understand what I am doing now - just need to get back to my latest sline version and follow it all through.

Will post the finished computer mouse when finished. :)

Thanks Heaps. :thumbsup: