Basic Human Form Tute: Merge polygons

# 1 18-02-2008 , 03:17 AM

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I am following along on the tutorial Basic Human Form and I really like the video and instructors delivery. Even when I stumble across differences between the version used in Maya and my own 8.5, I am still able to do a bit of research and pick up where I left off, however where the process breaks down completely for me is when it comes time to convert all of the nurbs to polygons and then join them.

The first encounter with that process during the training occurs when joining the head and upper body. The instructor assumes that everyone can do this without any problems and continues on with the lesson.

It would be most helpful at that point if he were to say something like, "now, if one or both of your polygons suddenly disappear when you invoke the Union command, then you should..." and then go on to provide some helpful advice and/or places to read up on the matter.

With a bit of trial and error I have managed to join the boots to the legs and then join both legs together. I still cannot join the head and torso though. I suspect the problem is with the way I developed the neck (protrudent) on the torso and the cavity on the bottom of the head.

When using Boolean commands like Union, is it absolutely necessary to create a "round peg" and a "round hole"? I ask because my neck is almost perfectly round, whereas the cavity of the head is squarish. As I insert the neck region into the head's cavity, there is no overlap of the neck ( sides of the neck) extending outside the cavity and the neck extends well into the space of the head. So, when I use the Union command I cannot understand why both polygons are disappearing.

Note: I am using the Boolean commands for Polygons and not nurbs.

Mesh > Boolean > Union.

Any help would be appreciated.

Michael

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# 2 18-02-2008 , 04:03 AM

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while i am no expert i simpathise, its a scary moment when all that work just disapears ... but to my knowledge it is just cos they are not intersecting ... in my experience the boolean needs no gaps to work and sometimes even then it can be finicky about edges and normals and stuff ... SO either flange out the top ring of your neck to get a good no gaps conection or just bite the bullet and do "polygon > combine and edit polygon > merge vert's ... good luck

"Climbing the walls of the 'Uncanny Valley"

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# 3 18-02-2008 , 04:06 AM

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further to above responce ... Kurt also Deals with this in "the Cartoon Dog Tut' and here he talks about it a bit more ... worth a look user added image

"Climbing the walls of the 'Uncanny Valley"

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# 4 18-02-2008 , 04:52 AM

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SO either flange out the top ring of your neck to get a good no gaps connection...

Okay. This sounds promising.

The cavity in the head was created by selecting four surfaces with a common border and then just deleting them. The cavity has no flange whatsoever. Is it possible that by just adding a flange that extends into the head's space, that there would be a surface area for the neck flange to attach to?

The neck is, basically, one big flange. It does taper off and I might be better off if I were remove as much of the taper as possible.

Does the Boolean command work better to join polygons whose faces are similar and parallel to one another?

user added image

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# 5 18-02-2008 , 05:53 AM

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yes i was thinking that my language may be an issue ... sorry ... and yes to the second diagrame with the elipse as oposed to the hex should be better. Essentialy you need to have all the faces intersecting and as close as possible, the geometry matching. Again have a look at the "Cartoon Dog" Tut' (its free dont tell any one) Kurt does a great showing of this and with step by step pictures he should get you way past this. its very clear

"Climbing the walls of the 'Uncanny Valley"

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# 6 18-02-2008 , 07:30 AM

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Success! Thanks for your help, Bruce.

I went back to my original "Frankie", the version where I hadn't cut out a hole in the bottom of the head; thereby creating a place to insert the neck.

Instead of making a hole I simply lowered the head onto the neck, ensuring plenty of neck "punctured" up through the head, chose Union and it turned both objects into a single polygon!

Another note of interest, I found that when I converted the torso into a polygon it had too many sharp, jutting edges and at first I just accepted it as the way things normally worked. I found, however, that the more isoparms I added to the model the smoother it looked when converting from nurbs to polygons.

My question is this; is there a performance hit, during rendering, if you attempt to cover a model uniformly with isoparms? I am assuming that the more isoparms you create, the smoother the model becomes but ultimately creates a burden for the computer. Is this so?

I have a pretty decent computer set up and Maya has two processors and at least 3 GBs or ram to work with and in the coming months I am sure I will find the threshold of diminishing returns for my system, especially when it comes rendering.

In the meantime I would like to convey my gratitude to you and the folks who maintain this website; for providing free assistance and the videos to cut my teeth on. I hope one day, to make a contribution as well.

Again, thanks Bruce, your help is appreciated.

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# 7 18-02-2008 , 08:55 AM

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just a breif reply to your point about converting to Poly's from Nurbs if you have a look at your Nurb form as to where the vertices are you will see them floating off the edge. A nurb is using these points to plot a curve so they influence the curve rather than sit on it where as a polygon is using these vertices as absolute points of conection between straight edges. So if you have pulled your original Nurb form hard to acheive the shape you wanted you will often have a few points poking out of your new polygon its easy to correct tho and the speed gain from Nurbs is well worth the oddity.
this should address your other question also about geometry and impact on render ... isoparms in nurbs equal edges in polygons equals more geometry ... so yes it will help to round off / smooth off your form but will add complexity to both further modeling and texturing and rendering ... it is a balancing act to get only as much as you need and where you need it you really have to plan it out ... there is lots of help out there tho so don,t fret user added image

"Climbing the walls of the 'Uncanny Valley"

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Basic Human Form Tute: Merge polygons

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