Varying Transparencies in Live Paint

Something I hadn’t considered before it came up at work was that it might be useful to sometimes have areas of varying transparency in a single live paint group. Live paint is a useful shortcut in Illustrator that people probably take for granted now, but it was probably originally a way of making things in Illustrator a bit more Photoshop-like for newcomers. Before live paint, you’d probably construct everything you needed to fill as a closed path, which makes a bit of planning and close attention to the stacking order of objects essential for complex drawing. With live paint, you can just draw and let those things take care of themselves for the most part. Read up here if you’re unfamiliar.

Anyway, one thing you can’t do without breaking your live paint group into separate closed paths is adjust the transparency of individual filled areas. Not in the usual way, at least. You can still select individual paths (and the fills themselves with the live paint selection tool), but if you look at the appearance panel you’ll find you still just have the live paint group selected — there’s no way to add a stroke to an individual path either. Take this giant butterfly:

An image of a butterfly against a background of the sun setting behind pylons. This image will be used to demonstrate varying transparencies in live paint groups.

He’s a live paint group, of course. Say I wanted his colourful wing segments to appear transparent, but the dark areas to remain opaque. The first clue as to how you can go about this is here:

The butterfly image as a live paint group filled with various patterns

You can fill a live paint group with anything in the swatches panel, including patterns and gradients. Patterns can be transparent!  In fact, if you make a transparent filled object and drag it to swatches, a pattern swatch is what you get:

Creating a pattern swatch with transparency

It’s just colour; it’s only attribute as a pattern is that it has 50% opacity. So naturally, you create a set and colour away with the live paint bucket.

The butterfly live paint group, filled with some transparent pattern swatches

Looks delightful! However, there’s one pitfall I’ve found of this method. It’s quite a niche situation, but could be critical if you fall into that tiny niche and can’t figure out what’s wrong. Say you wanted to add a stroke around your butterfly. You’d add it in the appearance panel, drag it below the live paint contents so it doesn’t visually cover the whole group, and then set knockout group so it doesn’t show through the transparent areas (read more about the very useful option knockout group here).

butterfly-pylon5

Pretty silly, but that’s what you want for some reason. Looks fine in Illustrator, but you’ll get a hint as to what’s wrong with this if you check a preview of it in Bridge or your OS:

butterfly-pylon6

You can see the stroke through the transparent areas! Knockout group should prevent this, but for some reason it doesn’t. You’ll see the same thing if you place the AI file in InDesign, or if you export a raster file such as PNG. This is because other applications can only view the PDF side of the AI file, and while this method works fine in Illustrator, something evidently gets lost in the translation to PDF. This isn’t great news if you actually need to produce something using this method!

Fortunately, there’s another way. Remember that you can add gradients to the swatch panel too, and these can also contain transparency. Obviously you could have any combination of transparent gradient stops, but if you just want to replicate what we’ve made above, you’d need a gradient with two identical stops, with the same opacity setting.

butterfly-pylon7

A bit of a pain, and rather odd, But for whatever reason, this setup translates fine into the PDF, and makes an image created in this way usable elsewhere.

Spray the spines on to a hedgehog

Recently I had occasion to draw a hedgehog tentatively handing his car in for an MOT, as hedgehogs sometimes need to do.

hedgehog-MOT-01

Doodling a hedgehog is simple enough, but how to take a holistic approach to drawing hundreds of spines? There are already a few different art brushes here to give his fur a bit of furriness, but I don’t think we want to be drawing an individual path for every spine too. Here’s how he looks without them:

nospines-02

At the moment he’s a sketch with a calligraphic brush (the black lines), filled shapes for the darker and lighter areas of his body (the brown shades), and some art brushes from Adobe’s Artistic_Paintbrush set to give him a bit of fluffyness (hedgehogs aren’t entirely spiny after all). So what tools do we have that can create and modify hundreds of objects at once?

The Symbol Sprayer tool!

Most approaches to drawing in Illustrator tend to be quite methodical — you draw in layers of discrete shapes, and people who come to it expecting to sketch and paint like they might in Photoshop can quickly hit brick walls with this approach. To me, the symbol sprayer always seemed a bit incongruous in this environment. What use could there be for something that randomly plasters your artboard in symbols? Well I finally found one. The key here is there is a set of tools behind the basic sprayer for modifying the symbol set (as it’s termed) after the fact. But firstly, we need a symbol to work with.

spine

This is just a symmetrical shape with a gradient fill, a couple of millimetres wide in our A4 document. Now we can get spraying.

spray

Go nuts with it. Set the density options (double-click on the tool) as high as they go and cover him. Use the square bracket keys to increase or decrease the size of the brush. Here the spin (rotation) is set to ‘User Defined’, so it initially appears random. After that it’s time for the scruncher.

scrunch-shift

This drags symbols towards the centre of the brush. Use it to pull any outliers into the large brown area of his back. Spray and scrunch until you have a decent density of spines, and your hedgehog will either have absurdly neat upright spines (if you left Spin as ‘Average’) or a complete mess (if you set Spin to ‘User defined’):

mess

I don’t think we can in good conscience leave him like that. Next up is the Symbol Spinner. This tool drags symbols to face the direction of movement of the brush cursor, so you can effectively comb him by dragging the cursor over the symbol set. Note the direction arrows that appear on symbols within the brush area:

brush

Just keep brushing him down until you have a nice neat hedgehog, who might feel a bit more confident about getting his car back:

neat

Slings and arrowheads

I’ve seen a few posts on the Adobe forums from time to time asking how one might ‘attach’ objects or symbols to path endpoints (or anchor points in general), so that you might have elements that move as you move points around.

arrowheads1

Like a lot of things in Illustrator, this isn’t really possible, but there are a number of odd ways you can accomplish things that might do the job well enough. I had a need to do something similar at work; producing a sort of annotation symbol for use by people who didn’t really have any Illustrator expertise, so it needed to be as simple as possible to manipulate. I went with custom arrowheads.

arrowheads2

I’ve got the appearance and stroke open there so you can see what’s going on. If you don’t know how to create your own arrowheads, Adobe provide the bare minimum of information here. There’s more info in the arrowheads file itself, but nevertheless there are a bunch of odd pitfalls and ways of going wrong, exacerbated as I was a CC user making an arrowheads file for CS5 users too. But after a bit of a struggle I had a nice bunch they could use, with some caveats. Ideally I didn’t want anyone moving the leader line from the horizontal, as this would happen:

arrowheads3

…and having symbols flying off at different angles just looked kind of unprofessional. So I was left trying to figure out a way of having a symbol stuck to one end of a path that maintained its rotation relative to the page, rather than the path. The clue to what I did is in the wording there. It’s a silly method, but within the confines of the page we use it works perfectly. Scatter brushes!

arrowheads4

Note the spacing: 9999%. This means you’ll see one instance of the brush every 100 times the maximum dimension of the brush object. Over half a metre in this case! More than we’ll ever need in a document 100 mm wide. The other key option is to have the rotation set relative to the page, so it won’t rotate as you change the angle of the path. This means although this is rather an awkward solution, the users shouldn’t see any difference, except the style now works as they wanted. Here’s the new path with its appearance:

arrowheads5

The top stroke has the scatter brush applied, the next has the arrowhead at the other end and the red swatch. The next two define the white backing to the stroke and the arrowheads respectively.