Splines from Hell...

[Kelley]

Every time I try to build a head, when I try to patch sections together, or fill ares by closing off with a spline, I get a complete mess like the pic. shown here. I try to pull and adjust the Bezier handles, but it nearly always makes it worse. I doing something fundamentally wrong, but haven't a clue as to what.

[robcat2075]

YOu'll want to show a wire frame too, but i see spots where you've got more than 2 splines goin thru a CP.

 

There are keyboard shortcuts to restrict Bezier handle motion, Someone will pop in with a link.

 

I find it easier to click-drag the gamma and magna values in the properties window.

[heyvern]

You need to play with and study how splines work.

 

In many cases entire faces can be created without fiddling with the alpha and gamma of the curves. I usually leave that for the final tweaking stage. The curves of a face should flow along the surface in a continuous smooth curve. If you join parts together and have extreme alpha/gamma changes you create bumps and creases.

 

As robcat said, make sure your splines are properly organized and connected. Stay with a "grid" layout of the mesh as much as possible. Use 3 and 5 point patches to avoid dead end splines that can cause creasing. Only tweak the alpha and gamma in small amounts to achieve a smooth surface. Don't rely on it as a "modeling technique". Later when you are more experienced and comfortable with alpha and gamma would you want to use it more... that's how I felt about it anyway. For the longest time I never TOUCHED alpha and gamma. Then I started to use it more to tweak the curves.

 

-vern

[Kelley]

Here's a comparison 3-shot. I see two of the CP's with more than two splines running through, but they don't seem to be the worst of the creases. Thanks for the help. Any suggestions on Spline Organization, and face modeling. I've got the TAO and A:M 2000, 2002 and A:M Complete Guide.

[KenH]

You really can't beat looking at existing model spline flow. But you should probably turn on the bias handles (if you haven't already) so you can see which way the splines are flowing easier. And pressing the PageUp key once will give you a better visual representation as to what's going on in shaded mode. Also, there's lots of great help in the past:

 

http://www.hash.com/forums/index.php?showt...;hl=spline+flow

 

Here's a quick explanation of some of the things not to do with splines. I think there's more but I can't recall them right now. I remember a mistake I made was when joining patches, I didn't break the splines....I just joined the side of each of the patches and expected the splines to merge into each other.

[3DArtZ]

to say it plainly.... the splinemanship is just unacceptable:)

its chock full of 3pt patches.

did you import this from another app?

[Fuchur]

Here's a comparison 3-shot. I see two of the CP's with more than two splines running through, but they don't seem to be the worst of the creases. Thanks for the help. Any suggestions on Spline Organization, and face modeling. I've got the TAO and A:M 2000, 2002 and A:M Complete Guide.

 

You are making a few very bad mistakes... it is all about splineflow.

I am not the best splinage-expert too, but as far as I can see you should avoid any "peaked"-looking splines in your model. That is never ever good.

Have a look at the image. I made a few changes to get a better (even so not perfect) splineflow.

 

In Short: EVERY spline in your image should have a flow and never end anywhere in a dead-end (exception: hooks, but even they should always be set with causion.)

BUT it should flow in a more or less straight way. For example at the beginning of the nose a spline is doing a 90° change, even so there would be a spline running quite straight to the other site. That is bad too. Always follow the other spline here.

NEVER ever try something like the 3-point-patch at the nose... that is really a bad thing

 

In my example there are a few semi-good-parts too, but they should render okay. Only bad thing about my splinage-methode is, that I am often using 5-pointers. Some people can avoid them better than me, but I never got into serious problems with them... As you can see I only made one site of the model... the other few lines are just to show where the flow should go.

 

*Fuchur*

[rusty]

Hi,

 

I don't think anyone mentioned this but along with the other suggestions you should always have a middle-of-the-model spline which runs exactly along Y0 (and BTW, the front should face the front). This spline should be one continuous spline. It looks like you do not have this. The reason you want to do this is because normally you'll only model one side then do the copy/flip/attach. You do this so a] you only have to model one side (less work) and b] you want both sides of your model -- especially a face -- to be exactly mirrored. You can change this later (though I wouldn't advise it) but while modeling you want it this way. The reason you want your model mirrored exactly is because, among other things, all of the AM tools and plug-ins depend on this and you'll want to use these ('other things' include ease of flattening or UV mapping, texturing, CP assignment and weighting and, animating).

 

Many times you will model both sides for sanities sake or so you can see what you are doing but then you delete one side and do the copy/flip/attach. Also, say you think you are done but then find you have to change something... make the change on one side the copy/flip/attach.

 

Anyway... my 2 cents,

Rusty

 

Edit: BTW, one time a friend modeled a car but when he placed on a 'path' with the 'Path' constraint it was upside down and pointed the wrong way! The reason was he had modeled it facing backward and also had found the model bone and mucked with it. It is the model bone that aligns itself on the path and it is the model bone which aligns itself with the 'world view' in the chor and, when in chor view, determines the pivot of the model.

[Kelley]

to say it plainly.... the splinemanship is just unacceptable:)

Yup. I had noticed that too. Actually, that posting is the end result of hours of tweaking and re-tweaking. Periodically, it's looked better, and just as often, it's looked worse. But not much worse. And all my mistakes were made in A:M. No imports. Clearly, there's something I just don't get about slpines. "Spline Flow" & "Spline Direction"...I'm not sure. Is it as simple as "direction-on-the X-axis", as opposed to "direction-on-the-Y-axis"? Or can the X-axis have two directions: moving-to-the-right, and, moving-to-the-left? How does one tell the direction a spline is flowing just by looking at Bezier handles?

 

In the diagram Ken posted, I see how the red line on the left is a problem. But the red lines on the right side seem to be accepotable four-point patches. What's the problem there?

 

I've been trying to apply the lessons tendered here. So far, with mixed results. I realize now that [for the most part] the CP's with more than two splines are the result of trying to extrude the nose outward. It would appear that this makes a spline on the Z-axis. For the sake of asking: is this as bad as it appears, or can an extrusion be done?

 

Randy: Thanks for mentioning the center-spline on the Y-axis. I'd been coming to the realization that this was perhaps crucial, not optional.

 

Vern: Will A.R.M. be up soon? I think there's some articles in there that I could use.

 

Thanks all for checking in.

[mtpeak2]

Ken's image is a little deceiving. I think what he was trying to show was this, which is not good.

[Kelley]

Ken's image is a little deceiving. I think what he was trying to show was this, which is not good.

Aha! The dreaded 'dead-end spline'! Thanks.

[3DArtZ]

I think a good way to get one into the proper mindset when laying out the mesh of your model

is to understand that "it really really matters how the splines are laid out".

You want the splines that make up the mesh to flow.

think of the eye socket in the shaded/wireframe model you posted.

you have 2 spline loops that flow nicely. Its pretty much the

only properly laid out splines you have in the model.

Also, you have 3pt patches everywhere. You use 3pt patches

only when no other 4pt or 5pt patch can do the job.

Understanding how to transition from spline loops to straight

flowing splines will help you solve many problems you would encounter when modelling,

for example in this image. Look for the patches that have 5points. this will help

you get out of most spline loops and into straight splines. Like for example

the arm flowing into the shoulders and into the chest/torso.

 

Mike Fitz

www.3dartz.com