Jul 2007
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Jul 2007
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mediajam
Jul '07

I am attempting to create a shader that will look like a medical illustration style of gauche or colored pencil. I know that this can be done with some extensive UV mapping and textures but I am looking for a more automated way of doing this. Something that would follow the contours of the object (currently I am working with all of the bones of the body).

I found this tree bark example and I might be way off track but...
Can something like this be modified to get the look I am interested in?
http://highend3d.com/maya/downloads/shader...eBark-1850.html12

Here is the look that I am trying to achieve-

bone.jpg747x323

I want the lines to follow the contour of the bone, that is to say if it was on your hand the lines would be parallel to your fingers, running the length of the object it is on. The way they do in the above image.

I am also open to methods that exceed my abilities. I am fine with this being allot of work now because I will be using it many times in the future. I am open to any and all methods, no matter how involved, although the more simple the better obviously.

Thank you for your time,
John

ptb
Jul '07

In my opinion you are thinking in the wrong direction.

Don't think about what material you'll need for your surface in first place, but rather what surface you will need for your material.

This will work with a texture with straight vertical lines... as long as your (perhaps nurbs-) Surface flows the right way it will bend as expected. Even if you create a shader which does this independent from the surface I don't think it will be that predictable as concidering the flow of the lines during modeling.

So, if you want to avoid "extensive uv mapping", then use nurbs. but i don't think you will be able to avoid good modeling, because the model is the place where the shader gets the information it needs.

joojaa
Jul '07

There is a trick you could use tough. What you do is you bend the shape section by section into straight vertical tube after modeling and use a 3d texture with this shape as reference. Now theres a alternatoive strategy toths and thats to measurew each points shortest distance to some base edge count and assign a avertex color for one channel tinto thid direction and then fluctuate the 2 other channels sightly from next value so that ou iterate their ditance change into a common variation. and then use thet vertex color along u and the distance fluctuation v. (they actually used the later in finding nemo but only in one direction) (reason you need 2 is that you have enough randomization directions to come up with a solution thats as far in all vertex directions)

But yes i agree nothing wins good modeling. If you look at that modell thees far more going on than the directions. however it is possible to paint the uv maps in

mediajam
Jul '07

Thank you both so much for your help.

I forgot to mention that my model already exists. I have purchased what is supposed to be on of the best models around so hopefully it's going to work for this. It is a poly model though.

If you want to see an example in Maya here is one vertebrae.
11http://medical.mediajam.com/bone.zip11

If I do need it to be in nurbs are there any secret tricks to convert poly to NURBS? Is this even possible?

Going with poly, does this change the above listed advice?

Thanks,
John

ptb
Jul '07

poly to nurbs is possible... make the polyobject live and begin drawing curves and lofting / patching them.

the only "automatic" way would be conversoin to subdiv and then from subdiv to nurbs... but forget it - wheres the point? with automatic conversion the surface only gets worse and you want a better one.

Yes, it's a lot of work, but hey, if this all was "automatic" I guess 16 year old nerds could do our jobs for 20 bucks :wink: . [well, of course actually not, but some clients would think so for sure.. ever heard the sentence "oh yeah, my son does this, too"? I'm afraid we'll be hearing this more often in the future]

Another way is to redo the uvs (i lookes at it - too many seams) and paint the textures (look into paint effects - as soon as you know how to create your own brushes you will be able to draw with brush-directions and pretty much what you are looking for) .

Another way is to wait if Joojaa comes up with more ideas ;-D.

hansesurfer
Jul '07

mmm...dont know about whats the best model around, but here, especially the proc. spinosus definitely doesnt look medically correct. Theres no vertebra looking like that. But I have no knowledge about the quality of that commercial stuff.
Better check that in a good medical book.

mediajam
Jul '07

I believe what you are seeing is due to the wide angle lens. Take a look at the .mb file. This model is a scan of actual bones. I work closely with some of the leading spine surgeons and tech engineers here in the US and they have not had anything bad to say about these.

Her is the model set that I am using.
http://www.3dscience.com/3D\_Models/Human\_Anatomy/index.php5

Her is another that I am interested in when they come out with the new version
3http://www.anatomium.com/3
It is based on scan information (MRI I believe) of living tissue.

But... I am getting a little off topic here.

j

hansesurfer
Jul '07

I had a look at these sites.

3DScience seems to be quite accurate, though either the scan quality is sometimes not really good or its just modeled (with medium efford).
Anatomium often seems to be pure fantasy, thats definitely not! scanned...

I hope you are sure its allowed to make the source 3D data public.

mediajam
Jul '07

Now we are getting pretty far off topic but I feel compelled to reply to this.

For the sake of this thread I believe that my use here is acceptable. I am a great customer of theirs as I have purchased every model they have. Prior to purchasing they sent me two of these vertebra for evaluation. In any case I have taken the file down so it is not public any longer.

I will also send an email to Zygote confirming that my use of the models in this way is acceptable. I believe that anyone interested in the bottom line that works for Zygote would see my (and your) actions/comments here beneficial.

Thank you for your concern though.

I will open another thread later today in Modeling discussing anatomy and invite you to join. I have spent a considerable amount time researching this issue.

Thank you,
John

joojaa
Jul '07

QUOTE(Ptb @ 07/24/07, 08:46 PM) [snapback]270323[/snapback]
[well, of course actually not, but some clients would think so for sure.. ever heard the sentence "oh yeah, my son does this, too"? I'm afraid we'll be hearing this more often in the future]

So you never expect anybody to encounter your dad, or any other 3d artists dad for thent matter, The fact that somebody says my son does that doesent mean hes son is 16 year old wannabe they could work a artists at pixar for all you know.

ptb
Jul '07

QUOTE(Joojaa @ 07/25/07, 03:08 AM) [snapback]270377[/snapback]
So you never expect anybody to encounter your dad, or any other 3d artists dad for thent matter, The fact that somebody says my son does that doesent mean hes son is 16 year old wannabe they could work a artists at pixar for all you know.

Hehe :wink: ... well, I was served with the further information after this question... Actually I had the feeling that this was the actual point -> "my son is so young and does the same thing... he's either a genius or your job is lame." . Well, but I remember my parents being fascinated by the rotating torus I did at the very beginning also :slight_smile: .

Besides that, I come across quite a few post-puberty-newbies who already get freelance jobs because they dump their prices down a bottomless pit and use a cracked maya. Of course not the big clients, but the smaller ones who think 3d has to be cheap and easy-to-do because nowadays its everywhere. And the smaller ones are important for the low- and mid-end freelancers who unfortunately have to begin to dump their prices, too (here in Germany).

mediajam
Jul '07

Any potential client who thinks 3D is easy is an idiot and you don't want to work for them anyway. I have been working with digital media for over 15 years and I have never felt like my head would explode until Maya. I have used and been instructor for many of the popular applications.

If you are finding your rates low, and you doubled them tomorrow, you would probably get less work, would it be half the amount? Wouldn't that be the same money? Now what are you going to do with all that extra time?

When I was just out of school working as a grip I stated my rate at about 125% to 150% of base. I was hired some times simply based on the assumption that if my rate was that high I must be good.

In some industries they say never discount, if you do your customers will expect it and wait for the discount.

Don't fall into the cheap trap. Get to the level that you know your work is top notch and charge top notch prices. If you have low rates you will get clients that call when they don't have any money, and unless you give it away it won't look top notch because the budget wasn't there. If you let them know your price is expensive they might not hire you now but they will keep you in mind that you are working for top prices and they might come back some time when they have a real budget.

It's the old adage... you get back what you send out. If you are projecting "I am cheap and I work real hard" you are going to end up working allot for no money creating junky looking work. If you project "I am expensive but I am fast and it's great work" then you will probably work less hours for more money and you will end up working on sufficiently budgeted pieces that look great on your reel.

I have hired someone at half rate that took three times as long and produced something not as good as someone who knew what they are doing and charged accordingly. Every time I try to skimp on talent cost I end up loosing.

A rock and roll attitude works in this industry too. "Let me know what you want and let's get started on it, or cut me loose because I have allot to do" (i.e. don't waste my time, it's valuable)

Most of all remember this. I know because I have been on both sides of this.

They need you more than you need them.

There are many more jobs that need doing than there are talented people to do them. No matter what the job, this is the case.

Having said that is anyone available for hire to do the above UV mapping?

joojaa
Jul '07

I agree ive actually needed to sever a contact because i gave a bit too favorable deal, and couldnt get rid of the job because of it. Frankly it was bottomless pit that ate time an effort and the money didnt compensate the fact at all.

ptb
Jul '07

Yes, seeing this as a "guide" I agree, too - but unfortunately that's not what a lot of people do (even some talented ones)... Actually it's not my problem, because until now I was very lucky: I never had to search clients, they always came to me :slight_smile: [I don't only do 3d, but also digital film - and parttime]. that's why I have no website, no demoreel, no advertising etc.

But that's not the usual condition and I don't know where you live, but here in Germany aren't too many jobs (there are many 3d artists who are happy for any offer). Probably because the last 5 years have been tough for german economy (now it's supposed to get better).