How Do I Choose Drawing Line Weights

Architectural Lineweights and Plotstyles

Over the years I have written a couple of items about line weights, plotstyles and the like, and somewhere in the depths of YouTube there is a video tutorial too, with terrible sound. I continue to get so many questions about line weights and plot styles, especially for AutoCAD. So, I thought it was about time I re-addressed the issue, updated everything and tried to give more of a complete overview of why line weights are important in architectural drawing and how to achieve this in AutoCAD.

Why do we use line weights in architectural drawings?

A line weight is the strength or thickness of a line, achieved by using a variety of pens with different nibs, or applying different pressures onto the paper.

Line weights are used in architectural drawings to demonstrate relationships between elements, create depth, scale, to create a hierarchy in the drawing and to add clarity to allow the viewer to better understand the drawing.

Not only do we use line weights in architectural sketching, we also use them in all stages of architectural drawing, both hand drawings and computer generated drawings. In the following post we will look at how to achieve different line weights when working in AutoCAD.

How to work with line weights in AutoCAD

There are a number of ways to set up and use different line weights in AutoCAD. These options include using layers to differentiate between lines that you want to be thicker or thinner. For example, all thick lines will be allocated to one layer, while all thin lines will be allocated to a different layer. The layers are usually named according to the item they are, for example all lines that are drawn to represent a wall, will be put on a 'wall' layer, and so on. Another simpler option is to have just a few layers, that are titled according to their line weight. I do not recommend this myself, as you do not have control over the drawing by setting it up this way, but I know it suits some people just fine.

I am going to go through line weights and plot styles the way I was taught. Remember, this is not the only way to do things, but this is the way that I know and use and it works well for me! It is up to you whether you choose to set your drawings up like this or not.

Once you have a set of layers that you like to use (read our layering standards guide here) – you can then go about assigning colours to the layers. The colours help to differentiate between the lines, but also identify the line weight of each line.

When we come to print, we assign what is called a "Plot Style" which tells the printer what colour and thickness each colour should be printed. For example, all cyan lines will be printed at a thickness of 0.35 in black, but all grey lines may be printed at a thickness of 0.18 in grey. You get the idea.

I would generally advise you don't use more than the basic colours number 1 – 10 for general drawing. It can get overly complicated if you assign hundreds of colours different line weights, it just isn't necessary.

These are my standard colour to line weight set ups:

Note that the last colours are printed as seen – this option in the plotstyle menu is 'use object colour'.

My line weights are on the light side, so you may want to adjust them to suit your needs.

I feel like the best way to really explain line weights and plot styles it to show you! The following video uses the FIA CAD template to demonstrate some of the key points of using line weights in autoCAD.

All of this line weight information is basically leading us to printing our cad drawings out as we wish to see them. This is a daunting process for a new CAD user, and can equally be quite complicated for people that have a good understanding of AutoCAD. The following outline shows the process going from cad drawing to printed drawing.

• Make sure you have set up your layers so that your lines are allocated correctly
• Make sure your layer colours correspond to the plot style you are planning to use to print
• Create layouts in your paper space so that you can easily allocate and save plot style and print layout and use publish shortcuts for printing
• Plot using the Plot command or publish command depending on your set up.

I recommend using a standard template file that you use every time you start a new drawing. I use the FIA Standard CAD Template, which you can purchase from the shop – however if you are looking for a free option, you can always download my free layer template and adjust it according to your needs.

Using a few standard plot styles

I tend to have between two and three plotstyles that I choose from. The first is my main style, which includes a few colours for site boundaries, hatch etc. I then have a completely monochrome option for black and white printing. Finally, I sometimes use an additional plot style for M&E drawings which have more colours available for demonstrating different electrical and drainage information. Rather than adjusting your main one, it is best to have a couple that you can go between as you need.

You might also be interested in:

How Do I Choose Drawing Line Weights

Source: https://www.firstinarchitecture.co.uk/architectural-line-weights-and-plotstyles/

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