Video Transcript
This QCAD tutorial focuses on the basic selection tools in QCAD.
Example drawing: back_plate.dxf
We will cover single entity selection and window selection. We will also have a brief look at the selection toolbar of QCAD.
Many editing and modification tools in QCAD operate on a selection.
To demonstrate the basic selection tools of QCAD, we have a look at this example drawing of a back plate for an electronic appliance.
We have already used some simple selection tools in previous tutorials, for example to select and delete a line.
We can click an entity to select it.
Notice how the selected entity changes its appearance, indicating that it's now active and can be modified.
To select a different entity, we click that entity.
The previously selected entity is no longer selected.
To add entities to the selection, we can hold the shift key while clicking entities.
In the same way, we can deselect already selected entities by clicking them while holding down the shift key.
To deselect all selected entities, we can click into an empty part of the drawing.
In a previous tutorial, we have also seen that we can select connected entities with a double-click on one of the entities.
This way a contour of connected entities can be easily selected.
The shift key can also be used in combination with a double-click to add other contours to the selection.
Just like with single entity selection, we can remove a selected contour from the current selection with a double-click while holding down the shift key.
Another selection tool we have already briefly encountered is the window selection tool to select entities within a rectangular area.
To select all entities within a rectangular area, we press the left mouse button at one corner of the area.
We keep it pressed while dragging the mouse pointer to the opposite corner of the selection area.
Note that the background of the selection box is blue and its border is a continuous line.
This indicates that only entities that are completely within the selection box are selected.
When we are happy with our selection box, we let go of the left mouse button.
Whenever we start our selection window at one of the left corners and drag it to one of the right corners, we are selecting only those entities that are completely within the selection box.
If we start the window selection at the right and drag to the left, we also select all entities that are only partially within the selection box.
We can use this for example to select intersecting center lines.
We press the left mouse button at the bottom or top right corner of our selection box.
We keep the mouse button pressed and drag the mouse to the opposite corner.
Note that for this selection mode, the background of the selection box is green and its border has a dashed line pattern to indicate that even entities that cross the border of the box are selected.
We let go of the mouse button when we have created the desired selection box.
All entities that cross the selection box are selected.
In this case, the center lines are selected.
We can use both window selection modes to select the top three rows of ventilation holes.
When dragging from the left to the right, we have to make sure that the circles are completely within the selection box.
When dragging from the right to the left, we only have to cross the circles with our selection box.
Even the circles that are only partially within the selection box are selected.
This is called a cross selection.
These are all the selection tools we can use when QCAD is in neutral mode, when no other tools are active.
In addition, QCAD also offers a range of dedicated selection tools.
We can find these in the CAD toolbar at the left.
Here we can for example find the polygon selection tool.
The polygon selection tool allows us to select all entities within a polygonal area.
We can for example select all ventilation holes by drawing a polygon around them.
This is a precision CAD selection tool, so we can use snap tools to precisely draw the polygon.
For this example, we want to only snap to grid points.
Note that we click the last corner of the selection polygon using the right mouse button to tell QCAD we're done.
Another selection tool allows us to select the entities that are intersected by a line.
With this, we can for example select a diagonal row of ventilation holes.
The last selection tool we want to demonstrate in this tutorial is one to select all entities on the same layer.
We click one entity to select all entities that are on the same layer as the clicked entity.
Since all ventilation holes are on the same layer, this is a quick way to select all of them in one go.
You should now have a good understanding of the basic selection tools of QCAD and be aware that there are more advanced selection tools.
Be sure to practice this with your own installation.
Thank you for watching this QCAD tutorial.