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A. Kitterman/Science

To 3D or not to 3D

Sculpting in 3D is like molding a piece of clay: You can push and pull at it, refine the shape of it, add pieces to or chunk portions out of it, and voila! You’ve made a model of something (perhaps a lump of clay!). Now imagine doing that in a space where you can’t touch your clay and you can only see one angle of it through a TV screen. Factor in 1996 computer technology (when I first tried my hand at 3D modeling), where each attempt to move your model in 3D space takes half a minute, and an hour to render its picture. Finally, add in ME, who had never even used Photoshop or Illustrator up to that point. It’s comical, trust me.

Having made my triumphant “return” to the 3D world 2 decades later, a colleague recently asked me a question: How do I know when to use 3D in an illustration? The truth is, I rarely know if incorporating 3D is a good idea or not. My default position is that if I think I can build it—or any part of it—in 3D, I try, even if there is a possibility that it doesn’t work and I don’t use it in the end.

Using a render (picture) of a 3D object in lieu of a 2D drawing obviously describes dimension more effectively, because it’s a picture of an actual 3D thing, like taking a picture of your cat or yourself. Actual shadows are cast by the object, and the solidity of the form is revealed in the changing gradation on the object’s surface as it gets farther from a light source.

The opening image illustrates these features. A macrophage (blue blob) is latching onto a tumor cell (orange blob). The portion of the image drawn in line describes the tumor cell adequately, but the weight of the macrophage and its grasp on the tumor is more palpable in the colored portion that is rendered in 3D.

I ask myself with every new figure: if I attempt it in 3D, can I finish the figure by the deadline? Will it be time well spent? My unbridled enthusiasm for 3D makes this decision a no-brainer: Of course it’s worth it! Sure I can finish it! However, the skill level of this particular 3D modeler does not always match said enthusiasm. Therefore, I assume my brain enters a decision-making flow chart:

A. Kitterman/Science

At the point where I ask myself if 3D helps clarify the subject matter, the two rightmost options in my mind are also valid reasons to execute in 3D. Think of it this way: If a figure isn’t eye-catching, a reader might not even look at it. I have thus failed at my job and should go back to school.

Revisiting our previous macrophage and tumor image, for scientific context, a macrophage’s job is to seek out bad cells, and then ingest and destroy them. Which portion of the image would you linger over? Which portion gives a sense of impending doom for the tumor cell? I know which my choice would be!

Another good reason to use 3D is that it can breathe life into an old topic. In the example to follow, what we’re looking at is how the same binding event occurring between two different sets of cells (left side versus right side) activates different pathways. Sounds pretty interesting, right? Unfortunately, this phenomenon is “well-known-and-therefore-not-very-exciting” to the immunology community at large. So how do I make this “tired-old-news” image interesting? That’s right: 3D!

I used 3D on the cell bodies to make them “eye-popping,” which then (hopefully) arrests the reader’s attention and want to know more. I didn’t get to beta test it, but in my heart it worked.

A. Kitterman/Science Immunology

Incorporating 3D objects into a 2D drawing can create an inconsistency in style. You may then wonder, why would we even mix the two? 3D objects tend to grab attention within a 2D landscape, so you can use this to your advantage if you want to emphasize something within a complex figure. In the next example, the molecular devices, which were the focus of the figure, are more prominent due to their 3D treatment, while the 2D chemical formulas become secondary, yet are still clearly represented.

A. Kitterman/Science

Conversely, there are also ways to blend 3D in with 2D. The next example is a three-figure set about the structure of the inner ear. The truth is I didn’t have the skill to build models for the left or the right figure. But I felt I could model the middle figure, which compares two different cross sections of capillaries. The layers of cells pressed upon cells on the capillary make it much harder to cross, and so using 3D to convey this impenetrability seemed appropriate. My worry then was how this full 3D figure would integrate with the two other figures drawn in 2D: Would it look mismatched? Could this model end up in my vast and rapidly growing graveyard of unused 3D?

A.Kitterman/Science Translational Medicine

Then, I realized that we face this challenge in the magazine all the time. While there are six individuals who create the published figures in 2D, 3D, or a mixture of both, all of the figures have the same “look” because we all use the same color palette, fonts, and design elements to stylistically unify the figures. Employing some, or all, of these design treatments helps unify the three figures, and further serves to “camouflage” the 3D among the 2D figures.

A. Kitterman/Science

So, what have I learned from my 3D adventures? Building a 3D model offers so much potential in many seen and unforeseen ways, and that drives me to continue building regardless of a triumphant success or an utter failure. A model can have a much longer shelf life than a 2D drawing, because once the model is built, it becomes part of a library (as shown above) from which I can use and reuse. I can take a picture of any model at any viewpoint, rather than having to draw each view separately. I’ve also used a 3D model as a template to help me draw a unique or unusual perspective for which I can’t find a reference. But ultimately, the very nature of 3D is that it is eye-catching. It is therefore always a good bet to try, because that’s what we’re after, isn’t it—to draw readers into the fascinating world of science? If 3D can be that tool for success, this 3D beginner says let’s do it!

Alice Kitterman is a Scientific Illustrator at Science.