Scientific illustration: Cell schematic

Generic human cell illustration. Click to embiggen.

I've recently been working on a piece that I thought might be of interest to readers of this blog as although it's not palaeontology, who can resist a bit of biology?

This is a 3D model created in entirely in Maxon's excellent Cinema4D of a cell that is gracing the front page of my day job website (www.stupond.com), and is a schematic of a generic human cell showing the basic structures and organelles commonly present in many cells. This could be animated or labelled is needed.

Next on the personal learning curve is getting to grips with Maya, one of the real heavy-hitters in the world of 3D modelling with a learning curve to match. Exciting stuff!

I hope you like the illustration.

Building a dinosaur - Triceratops takes shape

It was way back in September when I last posted about modelling a 3D Triceratops and since then there has been much yanking and tweaking of polygons, and the project has moved on (albeit rather glacially) a step or two. In that last post I talked about the technique I would be using to make the basic mesh, which was the extruding and manipulation of polygons. I chose this technique because a) It is one I use most often and b) it keeps things organised. However, after the aforementioned post Evan Boucher commented he preferred the polygon building method, where polygons are added individually to build a mesh and this too is an excellent technique; it's work checking out Evan's excellent website to see the results that can be achieved by this method.

The model in its latest iteration. This is a polygon mesh sitting within
a symmetry object, itself sitting within a hypernurbs object.

The image above shows the model as it stands now. This is made entirely out of quads, or polygons with four sides. The reason for this is it is easier to control the various polygons if things get complicated if they all have the same number of sides, plus when using hypernurbs the end mesh is smoother. Further down the pipeline when we want to add textures the model will be easier to manipulate to get the image maps in good order. Below is a breakdown of the model's structure.

The model looking down the sagittal plane.

As the screen shots show, I've only modelled half of the dinosaur and this is because I will use a symmetry object to mirror the mesh and create a whole model. This saves a huge amount of modelling time but does have some drawbacks, in that you mush keep an eye on the z-co-ordinates of your sagittal plane points or the mesh will have holes, gaps or puckers along the centre, and when finalised will have problem areas that will need fixing.

Half a dinosaur: the mesh in it's raw form.

This mesh is then nested first in a symmetry object and then in a hypernurbs object. The hypernurbs object rounds the geometry in an organic fashion and each polygon, edge and point on the mesh is weighted and this weighting can be adjusted to add or reduce the objects influence, for instance the tips of the horns are virtually unweighted to make them pointed whereas the points making up the edge of the frill are left at the default settings giving them an organic curve.

The mesh nested in a symmetry object, itself nested in a hypernurbs object.

The model with the symmetry object activated.

The form is roughed out and refined in stages to create the shape of the animal. This involves pushing and pulling points and polygons, constant referral to the reference and turning the hypernurbs and symmetry objects on and off to check your progress and make manipulation easier. At this stage we want to keep the polygon count as low as is possible so things don't become too confusing and it is worth getting onto the habit of making incremental saves of the project as you go along so if it does get muddled or looks wrong you can go back to a previous stage and restart.

The movie above shows a 360-degree rotation of the model at this stage. It doesn't need to be perfect at this point and should be devoid of detail, which will be added later. Of course, it needs to be as anatomically accurate as possible and any comments on this subject are most welcome.

Building a dinosaur - pulling polygons and symmetry

You'll recall from the last installment of this occasional series that before starting any actual modelling we needed to do the research. With that done, we can now start modelling Triceratops in earnest.

I use Cinema 4D for all my 3D work but the techniques I use are common to most major 3D modellers, with one notable exception, the mighty ZBrush which we'll cover later in the series. How you set up your production pipeline is personal to each individual and company, but mine is as follows:

Basic Modelling: Cinema 4D

Refinement and adding detail to model: ZBrush

Texturing: Bodypaint, ZBrush, Photoshop

Rigging: Cinema 4D

Animation: Cinema 4D

Rendering: (you guessed it!) Cinema 4D Advanced Renderer

Post production and compositing: Adobe After Effects

Before starting modelling I set up Cinema 4D (c4d) so I can model without having to stop and fiddle with lights etc along the way. So I create a basic matt pale grey texture, construct a standard 3-light setup (I actually have a master file I can import these elements from each time I start modelling) and finally add a floor for the model to stand on.

I then import any images I am going to use as reference for the model. This could be sketches, photos etc but in this case it's the skeletal Scott Hartman kindly gave me permission to use. I set this up in one of the views (in this case front) and use this as a guide to the proportions of my model.

Figure 1: The modelling environment; now all I need is a dinosaur to go in here . . .

Now we can start modelling. Luckily for us 3D modellers tetrapods display bilateral symmetry, which means they are they have the same layout on either side of the sagittal plane (see fig. 2). We too can use the sagittal plane as the axis for generating the mesh that will make up our model.

Human anatomical planes. As humans and dinosaurs are both tetrapods we can use

this scheme to assist in modelling our Triceratops. From here and used under

Creative Commons Licence.

To do this I use a symmetry object in c4d. This means any geometry created or modified is reflected along the chosen axis to create a whole model. By positioning a cube primitive with one side along this plane we can model one side of the dinosaur and the other side will be created automatically. Figures 3 and 4 show how this works.

Figure 3: A cube primitive aligned along the X-axis in c4d. The polygon against the axis

has been removed to make sure hypernurbs work correctly.

Figure 4: Drop the cube into a symmetry object, adjust the mirror plane to XY and viola!

Finally, the symmetry object containing the cube is dropped into a hypernurbs object, which automatically subdivides the geometry interactively to create organic forms; points and polygons can be weighted to adjust the influence the hypernurbs object has on the mesh.

Figure 5: The basic cube shifted so one edge aligns with the XY axis, dropped in a symmetry object

which is then dropped into a hypernurbs object.

Figure 6: The hierarchy of the basic starting mesh.

The hypernurbs and symmetry object can be turned off and on to help with modelling and previewing and you'll find yourself doing this constantly as the model progresses.

The technique I use for modelling is very simple. Extrude a polygon, adjust the points, extrude another and so on. Starting from this five-sided cube (remember we deleted the poly that is flush to the sagittal plane) we can create any shape we want. In the case of virtually all models including our dinosaur we want to rough out the body shape before we start getting to involved in detail. This basic rule of thumb, start simple and refine down gradually, and this needs some careful forward planning. Our dinosaur is basically one large, complicated shape and our mesh will end up as one large, complicated shape too. So we don't get lost, we need to pay close attention to the anatomy of our subject. We need to allow for the head and it's appendages, the limbs and their morphology and such details as the number of toes, the shape of the tail and so on. Where do the legs join onto the body? How does the neck articulate? How does the tail move? Think of these things before you start and the whole mesh as being divided down into ever smaller boxes and that's pretty much how the modelling process for this stage works.

Figure 6: Roughing out the body shape. This is the very basis of the model. I've extruded more

polygons from the original cube we started with and have begun to form the shape of the head,

body and tail. You can see I've not adjusted the Z co-ordinates at all, at this stage I'm only interested in

roughing out the form along the X and Y axes. The highlighted polygon will be where the shoulder

and front leg of the animal will be modelled.

So that's the start. Check out online tutorials for your specific modelling application for other techniques that will be of use as you progress, but remember the mesh has to be a single object, preferably made of polygons. Be thrifty in your use of polygons as we want to keep the polygon count as low as possible as they will soon mount up, and if we want to animate then lots of polygons could be problematic.

One more thing - don't move the points on any of the polygons on the X/Y axis (the sagittal plane) of the model, as this will create gaps in the symmetry later on, and you final model will have holes. Keep checking everything's in order by flicking on the symmetry and hypernurbs as you work, and correct any errors as you go along - do not leave them for later or you might get in one awful muddle.