An overview of working with Feature Selector.

Description

The Feature Selector node generates a grayscale mask from a selection of features in the input texture.

The node defines a feature as a region of pixels. The node identifies features in the input texture automatically. You cannot manually define a feature area, but you can use the node properties to influence how the node identifies features. For a list of available properties and what they do, see the Properties section below.

To create a selection from one or more features, you can bring the node into the 2D Viewport and use the node’s 2D Viewport Overlay. By default, the node creates one selection region, known as a segment. You can add and edit up to 3 segments, each containing a different selection region.

Alternatively, you can let ArtEngine automatically create segments with selections by using AI Assist with at least two mask inputs.

When you execute the node, it creates and outputs a black and white mask texture for each of the segments. The white pixels in this texture represent the features you selected. The rest of the texture is black.

Selecting features in the 2D Viewport

From the features the node identifies, you can select the ones to include in the output mask. To create and adjust a feature selection:

1. Bring the Feature Selector node into the 2D Viewport.
2. The 2D Viewport displays an overlay that separates the input texture into regions surrounded by black borders. Each region represents a single selectable feature. 
3. To select a feature, click on its region in the viewport. The region fills with the Overlay Color (by default, this is teal), which indicates that it is currently selected. To change the color and opacity of the overlay, see Properties.

When using the 2D Viewport Overlay, you can further manipulate the selection in the following ways:

• To add more features to the selection, hold Shift and click on additional regions.
• To remove features from the selection, hold Ctrl and click on a region you want to de-select.
• To invert the selection, use the Invert button in the node properties.
• For a full list of shortcuts, see 2D Viewport controls.

Using Lasso Selection

An alternative way to select features is by using the Lasso Selection tool. This allows you to draw a polygonal lasso by placing multiple points in the 2D Viewport. When you close the lasso, the node creates a new selection from the features that are inside the lasso area.

Note: The Lasso Selection tool only selects features that are completely enclosed within the lasso area.

To use Lasso Selection:

1. With the Feature Selector node in the 2D Viewport, press the L key.
2. A lasso icon appears in place of your mouse cursor. This indicates that the Lasso Selection tool is active. You can press the L key again to deactivate the tool.
3. To start a lasso selection, click the point in the 2D Viewport where you want the lasso to begin.
4. To add more points to the lasso, click elsewhere in the viewport.
5. To close the lasso, click the first point you placed.
6. By default, the node creates a selection from features inside the lasso area. You can use the Shift and Ctrl keys to add and remove the lassoed area from an existing selection, respectively.

2D Viewport Controls

Below is a complete list of shortcuts for working with the 2D Viewport Overlay.

Automatic selection using AI Assist

Two masks (above) and the corresponding segments identified by AI segmentation (below).

Feature Selector can automatically identify similar regions in the input image, and create selections from them, placing each selection into a different segment. To determine how similar any two features are, the algorithm uses a combination of surface texture and color influence. You have a degree of control over each of these in the Properties window.

To identify different regions, the AI segmentation algorithm requires at least two mask inputs in addition to the main input image. Each mask should roughly indicate a part of the input image that you want the algorithm to deem as a separate region. The mask does not have to be precise, nor does it need to cover most of the image. A few rough brush strokes are often enough for the algorithm to work.

For example, in a texture with bricks, you might use one mask to paint over a couple of bricks, and another mask to paint over some of the mortar.

To use AI segmentation:

1. Create at least two masks of the main input image. Each mask should roughly indicate a different region of the image. For example, the masks may indicate two areas of different color or surface material.
2. Connect the masks to the Mask1 and Mask2 inputs of Feature Selector.
3. In the Properties window of Feature Selector, enable AI Segmentation by ticking the box next to it.
4. (Optional) Change the Feature Bias and Texture Weight properties to fine-tune the algorithm behavior. Descriptions of these properties are available in the reference section at the bottom of the page.
5. Execute the algorithm by pressing the AI Assist button.
6. Once segmentation is complete, review the new segments created by the algorithm. For more information on working with segments, see the reference section.

Generating a mask from a selection

To create a new mask, select the features you want to include and execute the node.

The Feature Selector node outputs the mask as a texture, which you can export or use elsewhere in the Node Graph of your project.

Category and execution

Ports

Properties

AI Segmentation

This part of the Properties window contains settings that are specific to AI-assisted segmentation.

Segment settings

Below the AI Segmentation settings is a list of selection regions, or segments, present in the node. You can edit each of the segments and add or remove features from them using the 2D Viewport. The Overlay Opacity controls the opacity of the Feature Selector overlay in the 2D Viewport.

Each segment in the list has the following controls, listed in the order that they appear:

• Segment Name - determines the name under which the segment appears in the outputs of Feature Selector.
• Segment Color - controls the color of the segment overlay in the 2D Viewport.
• View Segment - enable to display the chosen segment in the 2D Viewport and enable editing for its selection region.
• Invert Selection - invert all selected features in the segment.
• Clear Selection - remove all features from this segment’s current selection.
• Delete Segment - remove this segment and its selection from the outputs of the node.

The Add button below this list adds another segment to the list, up to a maximum of 3.