When you create a new AutoCAD file, can you see this defpoints layer? No, unless your template file has it defined.
So when is it created? This layer will be created automatically by AutoCAD when you create dimension. If you don’t see this layer in your AutoCAD drawing, try to create a dimension, then look again in your layer list.
Now the big question: What is this layer for?
This layer is used for definition points when you place dimensions in AutoCAD. This layer by default is set not to be plotted. Don’t worry about this layer, and don’t use it. Why worry about one layer when you can create virtually unlimited layers in AutoCAD?
The problem is, many use this layer when creating objects they don’t want to plot. Viewports for example. The viewports border will be plotted unless you set the properties to non-plotted. This is practical before, as we can’t define a non-plot layer. Now that we can create a non-plot layer, we should avoid using this.
Why shouldn’t we use Defpoints layer?
Defpoints layer is somehow linked to Layer 0. When we freeze or thaw layer 0, you can’t modify objects in defpoints layer. You probably know it, but someone who receive your file might not. They might think the file is corrupt or their AutoCAD has bug.
The other reason is, when you run audit, all objects that are not dimension definition points will be removed to a new layer: $AUDIT-BAD-LAYER. There is no explanation whether this will make your files corrupted or not. But if audit treat it as ‘bad object’ then it we should be careful.
We don’t want to lose our important drawings do we?