I would use dia and extend it using the “sheets and objects” dialog.

I find inkscape to be serviceable (not excellent, but serviceable) for these types of things. You need to make heavy use of grids and guides though.

The link you give points to:
http://commons.wikimedia.org/wiki/Category:Chemical_engineering_symbols

So, some of the drawing is already done

If you get all the symbols, have a look for Kivio from the KOffice suite. I’ve used it before due to its similarity to Visio.

Also, have a look at Graphviz, for extremely complex drawings, scripting it is the way to go, but a bit difficult for noobs ;(

I can not believe that Dia would not have these shapes. They’re pretty straight forward to create. I’m in the Central Time Zone in the US, I’ll give it a try to make a couple of these shapes for Dia. You can find more about Dia shapes here http://projects.gnome.org/dia/custom-shapes

Justin: oh he’s quite capable of doing it himself, it just felt like duplicated work and yes, a surprise these were not port of a default set in Dia. May be that can be contributed back later on.

Did your friend look at the “Civil” and “ChemEng” shapes in Dia? Which additional shapes does he need?

If you’re looking for additional symbols:

http://diashapes.appspot.com/

Creating shapes in Dia is actually quite easy:

http://dia-installer.de/howto/create_shape/index.html

Creating shapes in dia is very hard and importing shape is really buggy.

1. In the documentation it said “Installing new shapes can be as easy as untaring a .tar.gz file to ~/.dia/shapes or $(prefix)/share/dia/shapes, with the sheet description going to ~/.dia/sheets”.

So this is what I did first: 1. creating a shape in dia, 2. exporting inside .dia/shapes/something.shape. 3. Wait. 4. Hmm.. no shape added to anything in the GUI. 5. Try to create a new shape in Sheets customization. 6. Open .dia/shapes/something.shape. 7. Cry because Dia erase my shape and the png. 8. Restart from the beginning. 9. Found that you have to put the shape inside a directory different than ~/.dia/shapes and let Dia copy it. Oh and OK don’t do the same than Apply.

2. You can’t import a lot of shape in one action.

3. You can’t open a .something directory because Dia don’t use GTK File Chooser for this file chooser.

4. Dia don’t register your last directory.

5. You can’t rotate shape by 45 or 90 degree.

6. I didn’t find any tool to remove, move or add “connection”.

7. When you create a custom shape with a Chem Tank, it creates a line in the bottom. It’s invisible when you create it. It’s pretty confusing.

Now, here is my work right now:
http://www.progysm.com/lab/dia/smesp-pipe.png

And it is not really useful if you can’t see shape picture in http://diashapes.appspot.com/.

Oh yeah, another thing you can’t do when creating shapes:
1. Take a png on internet with symbols.
2. Open the png in Dia.
3. Try to draw a symbol with line and triangle on the png.

You can’t because the line will automatically select the center of the png.

Inkscape with custom writed python extensions for jobs like, sanity checking, cross referencing, etc.

I used it for power engineering.

Use your canvas in pixel, but in a way that 1px = 1mm. So an A4 paper is 210×294 pixel.
When printing, stretch the page to the A4 paper, and everythings get rights.

In that way no rounding errors are in the .svg file, and manual editing/triaging bugs in the file “just works”. The ideal solution would be using a viewbox in svg, but it is not supported in inkscape.

Best regards,
Khiraly