Point groups are collections of associated points that are treated as a set. This is important because you can apply operations to them as a whole - saving you from having to apply discrete operations to each element. Furthermore, point groups can be used to filter-out points not needed for a specific operation; rather than affecting an entire input, grouping restricts the scope of an operation to the points in a group.
Creating Point Groups
To group points in the SOP Editor:
- Use the Select state, and in the sub-icons, choose the Point Groups icon.
- Select the desired points with the cursor.
- Call up the Parameters dialog by clicking the + button beside the sub-icons. Click on the Combine Groups page-tab.
- Type a new group name in the edit field.
- Click on the group <- selection button.
Ordered and Unordered Groups
A point group can be ordered or unordered. In the SOP Editor's Select state, a single click of the mouse button performs an ordered selection. Bulk selections are made by dragging the cursor across the points. This action creates a marquee box that encloses a number of points. Points selected in this fashion generate an unordered group.
The only time bulk selections generate or maintain an ordered selection is when only one point is caught in the marquee box. Unordered groups store their points in creation order; ordered groups store points in selection order.
If you want to reselect the points in the group, you can do so by calling up the Parameters dialog from the Select state, and selecting the group name from the Group pop-up menu under the Combine Groups page-tab. Then click on the button selection <- group.
When a point is deleted, Touch automatically removes the point from all the point groups it might belong to.
Each SOP has a list of Points. Each point has an XYZ 3D position value plus other optional attributes. Each polygon Primitive is defined by a vertex list, which is list of point numbers.