From a QCAD user:
How can I change attributes such as color, line type and line weight while drawing?
Using Layers
Attributes are typically controlled by layer in CAD. For each attribute combination, create a unique layer. Layers are essential in CAD. Each layer holds related entities (walls, dimensions, electrical, text, …). Related entities with the same function must have the same attributes. On a paper, we do not have layers and the function of an entity is solely defined by its attributes: a dashed line means the edge is invisible, a blue dashed line might be an electrical wire, etc.
Not Using Layers
The alternative is assigning attributes directly to each entity (“hard” or fixed attributes — e.g., explicitly coloring this particular line red regardless of its layer). This works, but it scales badly and is not recommended.
To change the current drawing attributes, you can use the Pen toolbar:
View > Toolbars and Widgets > Toolbars > Pen
To change the attributes of existing entities, you can use the property editor:
View > Property Editor
Why layers (with ByLayer) are preferable to fixed per-entity attributes:
- Global control. Change the Walls layer color from black to blue, and every wall updates instantly
- Visibility and printing management
- Consistency and standards
- Reduced error
- Cleaner files
- Drawing exchange, reuse.
The general rule: control appearance through layers, keep entity properties ByLayer, and reserve direct per-entity overrides for very rare, deliberate exceptions.
See also:
