Surface Control in Adobe Illustrator 3D

TLDR; convert spline points to smooth for less 3D surfaces to map

For a 2D application, Adobe Illustrator’s 3D effects are an impressive feature. The ability to apply UV maps with vector symbols makes it one of my favorite tools. I love having the ability to take any shape to the next level in a native and non-destructive manner.

Recently I needed to create a shape with a more detailed map that needed to line up across surfaces. The way Illustrator was interpreting my spline caused it to create 8 surfaces which made it difficult to ensure the symbol-map lined up across each one. I ended up creating a symbol out of the entire map and embedding it in yet another symbol for each surface. That way small adjustments would update across the polygon. I imagined myself teaching someone else this method and just shook my head.

After some investigation I discovered that Illustrator generates it’s UV islands based on not just the spline’s points, but their state as well. By that I mean a point set as a corner (independent handles) will split a surface into two. A smooth join however will keep it’s adjacent curves as part of a single surface. By selecting all of the points in my spline and converting them to smooth I was able to go from 8 surfaces to 2. That’s pretty huge as I only had to manage 2 symbol maps and had way more control over alignment.

Below I’ve detailed the steps involved while showing the before and after smoothing.

1. Create the spline or profile

First lets create a spline guaranteed to give us some corner joins. I use Object -> Path -> Add Anchor Points to place points exactly half way between corners so I can easily split the path in half later.


2. 3D rotate the spline and examine the number of surfaces created

Here is a demonstration of how many surfaces are created before any smoothing. 8 is a reasonable number for simple maps that don’t need to render across multiple surfaces but will not work for my needs. Notice that I Cancel the effect once I’ve tested.

3. Convert to smooth where possible and revolve

Here’s the real gold of this post. Illustrator has classically been able to convert a point using the Anchor Point Tool but can be tedious and distort the spline in some cases. Thankfully modern AI provides a couple conversion buttons in the shape toolbar. Notice that we now apply the 3D revolve we’ve gone from 8 surfaces to 2!

4. Creating a perfect fit

Unfortunately, AI doesn’t make it easy to provide symbols-maps with the exact same dimensions as its intended surface (UV island). In this video I demonstrate how using screen shots and Photoshop can help with that. Some scaling is required to line up the grid lines. The reason I use Photoshop to collect the screenshots is so that I don’t have to re-open or re-resize the mapping dialog box for each surface. I capture each surface, combine them in Photoshop and finally paste that into Illustrator for tracing.

5. Creating the symbol maps

Now it’s just a matter of creating the symbols to be used as our maps. Push, pull and edit as needed to fit your art onto each UV grid. Some adjustments may be needed once mapped. Any edits to the symbols after they’ve been mapped won’t show up until you open and hit OK in the 3D effect dialog. Notice that the light gray area is the actual surface. Anything in the dark gray area won’t render on the resulting polygon.

6. Applying the maps

Now we just simply pop in the map editor and apply our symbols. You will need to click the Scale To Fit button for each map. I had a few rendering errors the first so I merely had to move the symbol and click Scale To Fit again.

And there you have it! I hope this was able to improve your 3D workflow. Please leave any questions or comments you have below or hit me up at @ask_illustrator.

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