Linetypes are one of those AutoCAD features that you might use every day without giving them much thought. Continuous lines, dashed lines, centre lines and hidden lines all have a part to play in making drawings easier to read and understand.
AutoCAD comes with a range of linetypes ready to use, and you can load additional ones when you need them. You can also create your own custom linetypes for situations where the standard options don't quite fit.
Here's a look at how linetypes work in AutoCAD and how you can add your own.
What are Linetypes in AutoCAD?
A linetype controls how a line appears in your drawing. The simplest example is Continuous, which displays as a solid line.
Other linetypes use a combination of dashes, spaces and sometimes text or symbols. For example, you might use a centre line to indicate the centre of an object or a hidden line to show something that isn't visible in the current view.
Linetypes can be assigned to individual objects, but in most drawings it's more useful to manage them through layers. Setting a layer to use a particular linetype means that objects placed on that layer will automatically use it.
This is one reason it's worth getting your layer and linetype settings organised early in a project.
Loading Linetypes in AutoCAD
When you start a new drawing using the standard acad.dwt template, you'll have a few basic linetypes available, including:
- ByLayer
- ByBlock
- Continuous
If you need something different, you can load additional linetypes using the Linetype Manager.
To open it:
- Go to the Home tab.
- Open the Linetype drop-down in the Properties panel.
- Select Other.
You can also type LT at the command line.
From the Linetype Manager, select Load. You'll then see the available linetypes, along with their names and a preview of how they look. Choose the linetype you need and click OK. It will then be available in your current drawing.
If you're working from a company template, your CAD standards may already have the linetypes you need loaded, so you may not need to do this for every new drawing.
Where Does AutoCAD Store Linetypes?
AutoCAD stores linetype definitions in .lin files. You'll commonly come across:
acad.lin – the standard linetype definitions
acadiso.lin – definitions for drawings using ISO standards
These files contain the information AutoCAD needs to create each linetype. They are text files, so you can open them and see how the different definitions are written.
You don't normally need to edit these files yourself, but it's useful to know where AutoCAD gets its linetype information from, particularly if you're managing CAD standards across a business.
Creating a Custom Linetype
Sometimes the standard AutoCAD linetypes aren't quite what you need.
For example, you might want a line that includes a particular symbol or piece of text to identify a service, boundary or other feature in a drawing.
AutoCAD's Express Tools include a tool called Make Linetype, which can help you create a custom linetype without having to write the .lin definition yourself.
You'll find it under the ET Tools panel in the Additional Commands menu.
The basic process is:
Draw a sample of the line you want to create.
- Start Make Linetype.
- Give your new linetype a name and description.
- Choose where you want to save the linetype definition.
- Select the objects that make up your sample.
- Select the start and end points.
- Finish the command and load the new linetype.
Your new linetype can then be used in the drawing.
This can be a useful approach if you have a company-specific linetype that you want to use consistently across your drawings.
Keep Your Linetypes Organised
If you're creating custom linetypes, it's worth thinking about where those definitions are stored.
You can create a separate .lin file for your custom linetypes, which can be useful if you're managing your own CAD standards. Keeping company-specific definitions together also makes them easier to share with other members of your team.
The exact location of AutoCAD's support files can vary depending on your AutoCAD version and installation, so it's usually better to manage these through your company's CAD standards rather than relying on everyone having files in the same location.
Don't Forget About Linetype Scale
If you've loaded a linetype but it doesn't look right in your drawing, the problem may not be the linetype itself. Linetype scale can have a big effect on how dashed and patterned lines appear.
A linetype that looks fine in one drawing might appear almost continuous in another because the scale is different.
The LTSCALE system variable controls the global linetype scale. You can enter LTSCALE at the command line and adjust the value to suit your drawing.
There are also object-specific and viewport-related settings that can affect how linetypes are displayed, so it's worth checking these if you're having problems getting your lines to display as expected.
A Few Things to Remember
Linetypes are a relatively small part of AutoCAD, but getting them set up properly can make a noticeable difference to the readability and consistency of your drawings.
If you're working to company CAD standards, it's a good idea to make your preferred linetypes part of your templates and layer setup. That way, users don't have to load and configure them manually every time they start a drawing.
And if you need a linetype that isn't included with AutoCAD, you can create your own rather than trying to make an existing one work.
Need a Hand with AutoCAD?
If you're looking to improve your AutoCAD workflows or want to get more from the software, the TMS CADCentre team can help.
We provide Autodesk software, training and technical support for businesses across the UK. If there's an AutoCAD workflow you're struggling with, get in touch and we'll be happy to discuss it.
