Monday, April 12, 2010

Reconstruction Tips: Make your own skeletal references!

Alright artists time for...

Today brought to you by your friendly host Craig...

Hi everyone. My tip for today is how to make any skeletal reference work for you.

When trying to construct a scientifically accurate critter it is really important you stick to the proper anatomy of the animal. This means that being (pretty) precise on rough measurements and proportions of your creature are key. The best means to get these right is to use a skeletal reference.

However typically when you find such a reference it isn't quite what you need (if one exists at all!...).

I personally run into problems with pre-existing references as they are often in highly stylized poses, such as this Deinonychus skeletal reconstruction by Gregory Paul. These types of references though having excellently measured proportions and anatomical layout, make it hard for you to acquire useful information about how your animal is put together as the limbs are all folded up and angled in "weird" ways (okay not weird for the living animal [most of the time! sometimes people do impossible things in their skeletals]. However when trying to measure and compare proportions they are less than ideal!).

Further more if your reconstruction is in an unconventional pose, such as my 3D Deinonychus, it is really unlikely you'll find a reference already in your pose. In fact if you do find one odds are really good it is an over done conventional pose anyways!

Meaning if you want to compare your creation directly to a skeletal, you're almost certainly out of luck. Or you'll be forced to copy the preexisting pose. Which I urge you not to do! Too many people keep turning out the same general reconstructions. With an extra 20-30 minutes work you can come up with a reference that can be in any pose you'd like!

So how do you do get this personalized skeletal reference? Why you make it yourself of course!

I'll take you through how I made the reference that I used to cross check my 3D Deinonychus here. Now the pose I'm going for is essentially a dead laid out animal (needed for my 3D posing system), but you can use this procedure for any pose you want!

Okay so the first thing you'll need to do is load your reference into photoshop. I suggest right away saving it as a new file just in case. That way you have the original still at hand should you need it.
1. Your first real step is carve apart the parts of the skeleton that are at the wrong angle for your purposes.

Some general tips:

Make sure your taking things apart at the joints. You can also take them apart a lot more thoroughly than I have here. Each vertebrae and digit bone can be separated if you want. I haven't gone this far, but you'll note I did separate a few individual neck verts.
Think about giving each separate bone or limb its own raster layer in photoshop. This makes it easier to manipulate them one at a time, and not risk wrecking your other parts by accident.
2. With your picture editing software's "Free Rotate" function manipulate your individual bone elements to your desired angles.

Some general tips:

Learn your undo hotkeys for this stage. As it can take some trail and error to get things to look right.
Have a protractor on hand if your program only allows manipulation by typing. (Some photo editing programs will have nice built in rotation tools that you can with your mouse just twist selections around in your drawing window. Sadly my version of Coreal Paintshop Pro only allows me to rotate things by manually typing in the number of degrees I want it to rotate by. Thus I can not be as precise to start off with unless I have a protractor to look at)

Once you have your piece oriented roughly how you like, lay them out close to their final position to double check. Here is where separate raster layers can be handy, as you can lay them out in their final position, and move them after the fact if you don't like them.

3. With your parts oriented correctly put them all back together!
General tips:
Keep a copy of the original picture handy, so that you can make sure you are repositioning all the joints back in exactly the same place.
If you were using separate layers save a copy of your skeleton in a layer supporting file format. That way you can repose this skeleton again in the future if you ever revisit it!
Okay so once you have your own version of the skeleton you can use it to your hearts delight.
The way I use it, handy for anyone working in digital medium, is my transparency overlay technique (which you can read all about here), seen here.
In my case having built my raptor before I had the skeletal reference, I could now see I needed to fix it...
Just like that my 3D Deinonychus was pretty much spot on (with a few tiny variations, but I'm fine with 90% accuracy... the animals would have all varied individual to individual anyway).
Outside of my example I'm hoping you can see applications for this technique in your own work!
On the last topic of what if there is no pre-made skeletal reference for your current animal project?

Well if you have a half descent photo of the actual fossils, my technique works just fine on them too!!!

So good luck in the future with your own skeletal references!


Brian Blacknick said...

Very slick technique Craig! I don't have photoshop so I'm usually stuck cutting apart the skeletal drawing with an Xacto knife.

Albertonykus said...

Astounding! That's a wonderful technique.

Nick Gardner said...

interesting, but FYI,those knees are horribly overextended...

Glendon Mellow said...

This is a fantastic explanation of 3D technique! That could work wonders for medical reconstruction and illustration too.

Bravo Craig. Thanks for this.

Nick Gardner said...

for medical imaging, most people make use of data that is already 3D generated by CT or MRI scanning.

Weapon of Mass Imagination said...

Thanks y'all...

Brian- You don't need photoshop for this technique, just any program that allows you to rotate parts of images (Paint is probably too simple, but most anything above it will work). There are probably many free programs you can use to try this. Be a lot quicker than cutting everything out ;) (Though I guess for your stuff you'd want it on cardboard too, won't you?)

Albertonykus- Cheers buddy. It really isn't that hard either!

Nick- Thanks for the heads up, but I did know that :P

The way my 3D program works is that I build the model, and then tell the computer where joints are. This than allows me to bend those specified body parts.

If I pre-sculpt my knees bent (which I know were basically bent all the time in theropods) it distorts them if I bend them after adding the joint. I suspect this is due to my software being optimized for 3D humans...

Before posing him, I needed to make sure my arms were the right length compared to the legs. Which in the first draft was correct (I'd managed to stretch the neck and torso somehow though).

Now that he is all the right proportions I'll be getting to bending the knees so that he is happy again.

Glendon- Ah shucks!

I really should do some proper 3D technique tutorials one of these days. To be honest this was all 2D technique, that I use to cross reference my 3D stuff.

Mine can be quite cross field artworks in the end!

Brian Blacknick said...

Craig I generally lay the skeletal drawing over a sheet of thin basswood and cut my parts out of that.

El Museo de la Luna said...


Rachael said...

I wish you'd posted this sooner - I too have been cutting up bits of paper with a scalpel!

Mind you it's probably still quicker for me as I'm a complete techno numbnut. I've learnt a great deal from this site though in the past year.

Another useful and interesting insight Craig. Please, please do a piece on using photoshop to add backgrounds and pasting from one image to another as I'm having real trouble.
It's a useful tool for building a resource and trying and testing for composition but if I get it to work once I've forgotten how to do it again the next time. D'Oh!


Nima said...

Great insight Craig!

While I don't do any 3D computer-generated work (yet!), I agree having good skeletal references is very important.

Even more important is being able to construct your OWN skeletals or at least rough diagrams of them from published photos and measurements when you can't find any good skeletals - or when they just plain don't exist (as was the case with my Puertasaurus and Argyrosaurus submissions to the Sauropods gallery).

I think there should be a whole post on the importance of making good skeletals for less well-known species. Any takers?

Weapon of Mass Imagination said...

Brian- The wood makes sense. I should have realized that.

El Museo de la Luna- ;P

Rachael- It seriously isn't that hard. I swear if you give it a few hours playing and tinkering you'll get good at it.

However I'll throw together something soon just for you ;)

Nima- I personally use this technique on all obscure skeletals. I just use similar animals skeletons (whether ink or fossil photo) and use them for overall proportions.

I've found that things with really out of whack proportions get proper skeletal treatments typically, otherwise they tend to match known things (or are so scrappy you can safely make it up).

However if you have a technique I'd love to see it! So I'd say you just raised your own challenge ;P