Blender: tutorial: Fun with nurbs

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Fun with nurbs				2001 01 03
	Timothy Paulus Henricus Kanters			id117

Introduction

By Viacheslav Slavinsky (svo) and Timothy Kanters (Kib_Tph).

In this tutorial you'll be making your own cartoon style mouse head like you see on the image, using the blender Nurbs feature. Why nurbs? Because it's a very fun and relatively easy way to make nice and detailed characters. When you finish this tutorial you will know the basics of Nurbs and then you can try to apply your knowledge and make your own cool models. To be able to do this tutorial you are required to have some knowledge about the basics of Blender. If you don't have this knowledge try some of the simpler tutorials first.

I hope you'll have a lot of fun while working on this tutorial.

The final result

Adding the surface curve

The first steps

All this starts exactly like Bart's cave tutorial on skinning. First delete everything in the scene (by selecting everything and pressing

), then make sure you're in front view (

) and press

then add >> surface >> curve. It's very important to use a surface curve and not a regular curve. The difference between the 2 is basically that with a surface curve, blender can calculate the so called skin of the object, but we'll get to that later on in this tutorial..

Closing the curve

We now have an open curve. This is our base curve and we will create the entire model out of this single curve by using modeling tools like extrusion, subdivision and smoothing. However we want the curve to be closed, so simply press

once to close the curve. Watch out that you only press

once, if you press it twice, the curve will open again.

Getting more control

First we'll start by making the mouth of the mouse, we will need a bit more control, so we'll subdivide the curve. Now we have a nice amount of control vertices (CV's). Subdivision ruins the geometry of our curve hence it is important to adjust it after every subdivision. It's also vitally important to maintain horizontal symmetry. Never move CV's left or right, instead, always select two and scale with

. So now you can model the basic shape of the mouth (as you can see on the image).

The basic shape of the mouth

Use your imagination

Wow a mouth!!!

Now leave edit mode (

) so we can duplicate some curves with

and give them some shape, you can use rotate

, scale

and grab

to do this. If your 3D imagination isn't yet advanced enough to imagine what to do exactly at this point, just make something like what you see. It can also come in handy to look at the next few steps before doing this one, as it will give you an idea of what we're trying to do here. You don't have to be to precise, asany mistakes can be easily corrected later on.

What you see now are basicly a few nurb circles as separate objects. We want to create one object out of those curves. So lets select all the curves with

and join them together using

. Now that all the curves are one object we can add the so called skin to the nurbs, so first go into editmode

and then select all CV's (

) then press

to skin the nurbs curves. When skinning nurbs curves you have to make sure that they all have the same amount of CV's or else blender can't skin them.

Joining the curves

Isocurves are parametric curves that form the surface. When we performed the first part of this tutorial, we prepared V isocurves. When we skinned them, we (or to be exact, Blender) added U isocurves. Think of them of some kind of a smooth grid with silk skinned on top of it. If you move one junction the surface changes, but smoooothly.

Setting up our surface

Our setup

Enter editmode, select all (

) and press "Endpoint U" in the editbuttons menu. Do not press Endpoint V (they are uniform now), because it will ruin the tubular shape of our creation. You may try it and then switch back to Uniform. I also find it is not enough to work with the default resolution. Usually for a start I set it to something like 24/24 or 32/32.

The resolution affects the level of nurbs surface tesselation when it's being rendered or drawn. You can see how the density of the wireframe surface changes, so choose a resolution you like. I would also suggest to leave the order as it is - 3/4. I will not explain to you in detail what the order means but you can find out for yourself by doing this; open a new blender window create something like a nurbs circle and duplicate it a couple of times then for each circle set a different value and then you can see what the value changes or causes.

Adding an extra curve

Working towards the nose

Now it's time to get busy shaping. Your friend is

. Select a CV, press

, it selects one isocurve along either U or V. Press it second time, it changes the selection from U to V and vice versa. This helps in first time shaping and in subdivision.

On this image it looks like the two outer isocurves are not subdevided enough so we're going to add another subdivision. We first select a CV on the outmost curve (far right), press

to select the full circle. Then select a circle of CV's next to it (don't forget to hold

while selecting more CVs). Now press

and choose subdivide. And there you have it an extra curve.

Never subdivide before you're absolutely sure you can't get the shape you need without more subdivisions because the more CV's you have the more complicated your object gets, and the more difficult it gets to deform it. Maybe you can drag some CV's from somewhere else where they are not necessary? Maybe just move them in some other way you didn't think of yet? If it doesn't work, subdivide.

Shaping the nose

Now it's time for you to start shaping the nose, just select the CV's and move (

) them. Make sure that you always select atleast 2 CV's so that your shape stays symmetrical. You can shape the surface by using regular modeling tools, like grabbing and moving (

), scaling (

), etc.

A nice and plumpy nose

Now we're going to try and make a nice and plumpy nose for our little mouse. Look at the final image to see what we want to achieve here, so you know what we're doing.

Nice and plumpy?

It looks like more V subdivisions are necessary to make that nice plumpy nose. Select V isocurves, and subdivide (

) them. Let me remind you of one thing I said earlier in the tutorial: when you subdivide, the geometry of surface changes. If you subdivide in favour of some particular detail, the "parasite" CV's accumulate on the other side. Never subdivide two curves several times straight. Instead, subdivide, adjust the shape of the whole object, and see if you need more subdivisions. If you do, go on, but it often turns out that you don't. And also keep in mind the symmetry of your object. I can guarantee you, that it makes it a whole lot easier.

Making more V subdivisions

After some more shaping of the nose we get something like this. The nose isn't perfect yet but it's getting there. For now lets leave the nose alone and move on to the eyes.

Now that's what we call plumpy!

The location of the eyeballs

The eyes

We've reached perhaps the most scary part of any face, the eyes. Scary because the level of detail they have is often very high. Let's add an eyeball as a separate object. It doesn't matter what kind of a sphere it is because it is going to stay round. I think it's better to have a mesh UVsphere here. So, add one, duplicate and adjust them. Find a good position for them. If you have a sketch, use it or you can of course look at where I've put them.

Wow we just made some eyes

Here you just need to move your CV's like insane to get the desired result. we need to increase the number of subdivisions here. And then just try folding the CV's around the eyes.

A closeup

After serious shaping of the eyes we most likely get creases. Try to smooth (

) them very carefully. On this figure I added another subdivision to tumble out the seam. Be careful and do not add more seams by adding a subdivision.

Finishing up

Now the eyes are finished try working a bit more on the nose and mouth, like I did right here. The mouse head is almost finished. You can do the ears on yourself that should be no problem, you managed to get the eyes done, after all.

Almost done

Here you see the mouse head complete it still needs some smoothing but you can do that on your own. After you've finished this head you might wanna try textureing it, or completing the mouse and making an entire body for it, perhaps animating it or whatever. Well, we hope you had a good time doing this tutorial, and we hope you learned alot doing it.

Download:

mouse.zip

The End result