Best way to create an art brush for plumbing pipework

[David C Anderson]

I have created a plan of my central heating pipework that provides a good indication of how it looks in reality rather than being a simplified diagram. To do this, I first created art brushes for 15mm, 22mm, and 28mm pipes. Each of these brushes simply has a pair of lines defining each side of the pipe.

However, it would have been better to have had a fill colour for these brushes, but my attempts to add a fill that is limited to the line of the pipe have failed. Is there a way to do that?   

[Doug A Roberts]

Probably? Please show your brush artwork and what you've tried so far.

[David C Anderson]

I've attached a JPEG export of my drawing (created in Illustrator CS6). All I've tried is to add a fill to sections of the pipework and it doesn't achieve what I want, which is to add fill colours to the pipes and nothing else.

[Monika Gause]

If there are just 2 lines, then you cannot fill anything. Just drawing a white rectangle and putting it behind the 2 lines could be an option.

[Doug A Roberts]

How exactly did you try? Does this work for you (a coloured rectangle between two strokes)?

[David C Anderson]

I'd already tried that before I started this drawing. It doesn't work for me (using CS6) as it does for you. Your example shows the red fill colour being confined to the interior of the stroke throughout a bend. In my case, the fill spills out across the black border into the area inside every bend. Are you using Illustrator CC?

[Doug A Roberts]

Please show what you tried. I am using CC, but brushes have not changed between CS6 and now.

[David C Anderson]

This is what I tried:

[Doug A Roberts]

Can you share the brush file?

[David C Anderson]

I tried to attach a brush library containing my 'Art brush for pipes', but got an error about its extension not matching its contents.

[Doug A Roberts]

You can't attach AI files in the forum unfortunately.

[Luke Jennings3]

I believe you could attach an .ai file to a pdf, and then upload it using the "browse files to attach" button. In Acrobat- View> Show/Hide> Navigation Panes> Attachments> +

Or possibly just change the extension to .pdf, then change it back after download.

[David C Anderson]

It seems rather perverse that a forum dedicated to Illustrator won't let you upload Illustrator files! I've changed the extension of my AI file to PDF, as you suggested. I hope it works this time. 

[Doug A Roberts · Accepted solution]

The problem with this brush is that the outer lines have a fill, which appears when their endpoints are separated. Remove the fill from those outer paths and it should work.

[David C Anderson]

Well spotted! That does indeed fix my issues with your method.

I've already converted my original drawing to use Met1's multi-stroke line suggestion. It will be interesting to find out if your brush solution is any better. At first glance, there doesn't appear to be much of a difference. 

[Doug A Roberts]

Brushes give you more options for terminating your paths in interesting ways (you could draw couplings at either end, for example) but otherwise there should be no functional difference.

[David C Anderson]

How do you create end couplings for brush strokes?

[Doug A Roberts]

Say you wanted something like this:

You'd select 'Stretch between guides' and pull the guidelines away from the ends so the centre section is the only bit that deforms. Then you could make parts like this:

[David C Anderson]

Thanks for that very useful advice. It's much appreciated. I don't need to create such complex ends for the pipes in my current drawing but this method may well prove useful for other purposes. 

[David C Anderson]

I've just used that method to create an art brush for a pipe with one end rounded off. That will be useful for pipes that are connecting to tanks, etc. Previously, I was adding such ends manually.

[Doug A Roberts]

Good to hear. If there are any other variations you need to create with a single path, there is probably a method (or several methods).

[Met1 · Accepted solution]

How about a simple line with two (or more) strokes...

[David C Anderson]

That suggestion appears to work very well. I didn't know you could create lines with multiple strokes., so thanks for advancing my knowledge of Illustrator  🙂

[Luke Jennings3]

Create a small rectangle.

Fill it with a gradient from the Windows> Swatch libraries> Gradients> Metals (or create your own).

With the rectangle selected, go to Object> Expand.

With the rectangle still selected, go to Brushes> New Brush> Pattern brush.

Apply the new brush to any line.

You can round the corners using Effect> Stylize> Round corners.

[David C Anderson]

I'm trying to follow your suggestion, Luke, but keep getting the error 'The selected artwork contains an element that cannot be used in a pattern brush'. I have tried several different swatches from the Metals Gradients, including Pewter and all have generated the same error.

What might I be doing wrong? What settings are required in the Object > Expand dialogue box (I used the defaults)?