Tutorial: 2.7 Selection Filter

In this QCAD tutorial, we check out the selection filter of QCAD.

The selection filter is a powerful tool to select entities that match certain criteria.

Example drawing: map.dxf

We will learn how to select entities based on their type or their properties.

The selection filter is a widget, similar like the layer list or property editor.

We can show the selection filter by clicking the filter icon in the toolbar at the right.

The selection filter widget is now displayed at the right.

This example drawing contains a section of a city map.

The map contains lines that represent the various geographical features of the area such as the roads and buildings.

There are also text labels with additional information like cadastral numbers.

As we can see in the layer list, this drawing is not properly structured with layers.

All entities reside on the default layer "0".

The selection filter of QCAD can help us to still work efficiently with such a drawing or to reorganize the drawing with layers.

First, let's put all text labels on a dedicated layer called "Texts".

For this, we need to select all text entities in the drawing.

We choose the entity type we want to select in the selection filter widget.

We can now click the button at the bottom left of the widget to select all text entities.

This button selects all entities that match the current settings of the selection filter.

We can now add a new layer based on the current selection.

We call our new layer "Text".

We make sure that the current selection is moved to the new layer.

All text entities are now on their dedicated layer.

Most of the text labels are cadastral numbers shown in yellow.

We select all of these yellow text labels and move them to a dedicated layer called "Cadastral Numbers".

For this, we need to filter the text entities based on their color property.

We choose "Text" as entity type again.

We choose "Color" as property to filter.

We choose "equals" or "is" as comparison operator.

Finally, we set the value to "Yellow".

We can now click the button at the bottom left of the widget again to select all yellow text entities.

We add a new layer based on the current selection.

We call that new layer "Cadastral Numbers".

Again, we want to move the current selection to our new layer.

All yellow text entities are now on their dedicated layer.

The selection filter can be used with four different selection modes.

The most common mode is "Replace Selection", which replaces the current selection with the entities that match the filter criteria.

The second mode is "Add to Selection", which adds the entities that match the filter criteria to the current selection.

The third mode is "Remove from Selection", which removes the entities that match the filter criteria from the current selection.

The fourth mode is "Intersect with Selection", which retains only the selection of the entities that are both in the current selection and match the filter criteria.

We demonstrate this again by selecting the orange text labels in the drawing along with their circles which indicate their exact position.

We can see one of these orange text labels with its circle here.

First, we select all text entities with orange color using the selection filter in "Replace Selection" mode.

Next, we use the selection mode "Add to Selection" to add the circles with diameter of 1 to the current selection.

All orange text labels along with their circles with a diameter of 1 are now selected.

We move the current selection to a dedicated layer called "Reference Points".

The selection filter offers many more possibilities to select entities based on their properties.

One more example use we want to show is to select all texts that start with a given prefix.

For this, we set the entity type to "Text" again.

We set the property to "Text", meaning we want to filter based on the actual text content.

We set the comparison operator to "starts with".

We set the value to "17" to select all texts starting with "17".

We click the button at the bottom left of the widget to select all matching text entities.

All text entities starting with "17" are now selected.

This way, the selection filter can be used like a search tool to quickly find entities with a set of given properties in the drawing.

You should now know how to use the selection filter of QCAD to select entities based on a given set of properties.

Be sure to practice this with your own installation.

Thank you for watching this QCAD tutorial.