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Development Notes
Selection Behavior

Intro & Interface
Primary/Trim Objects
Infinite/Special Trims
Active Editing
Panels & Alerts

The info on this page is just a quick overview of aspects related to the new v3 Boolean Modeling Tools.

The GroBoto Documentation PDF has more general information on GroBoto's standard primitive modeling.

For more on v3 Tools and Methods see:

Boolean Modeling
Mesh Creation
Interface - Mac OS X
Interface - Windows
v3 Videos

GroBoto Coordinate Systems:
Cluster Size Limit - A single Boolean Cluster can have a maximum of 32 GroBoto Primitives — attempts to add more should not cause any problems (but we can't be sure), in any case, they will be ignored.

Valid Trim Objects - Only a few GroBoto Primitives are supported as Trim Objects. See Intro & Interface on this page. We will be expanding the Trim Primitive set (and the ways they can be used), as we go.

Textures - Textures work with Custom Booleans, but you may notice some quirks. Textures do not seamlessly wrap around Boolean Clusters (like they do with simple Primitives), and you may see a big difference in texture scale on the surfaces created by Trim objects. We recommend not using Textures while creating/editing Booleans, the can decrease performance significantly)

Bots & Ducts Unsupported - Boolean Clusters can not be used a Bot Primitives. Likewise, normal GroBoto Primitives that belong to an AutoBot can't be used as Boolean Cluster objects (they can be used once detached from the AutoBot). Ducts are not supported in any form.

Flex Tools - Currently Flex Tool behavior of Clusters (and individual Cluster elements) and is undefined. Upcoming builds will bring Flex functionality to Custom Booleans.

Selection Behavior
GroBoto treats Boolean Clusters as normal, single primitives (when not being actively edited). Selecting an inactive Cluster automatically selects all of its Primitives, including its hidden Trim objects. Any GroBoto interface item that shows selected object counts reflects those hidden Trims.

Sometimes you want to edit individual Cluster Primitives in an inactive Cluster. We provide two ways of overriding the auto-selecting of all Cluster primitives:

Keyboard Selection - Use Alt-A (instead of the usual ‘a’), with the cursor over the object you wish to select.

Selection Tool - Use Alt-Click with the (make sure the ‘Select Single’ Option is checked in the Edit Panel).

See Active Editing on this page for additional selection features and notes related to editing Clusters.

'Select By...' Options may not work correctly with Boolean Clusters. (Edit Panel's Select by Group, Select by Type, etc. in - and their keyboard equivalents). For now, please use the ‘a’ key or the Select Tool with the ‘Select Single’ option.

Boolean Glossary

Cluster - A collection of standard GroBoto Primitives that combine to create custom, editable Boolean forms.

Type - Every Cluster consists of two Boolean Object Types:

Primaries - The foundation Primitives that form the maximum extents of the Boolean. A ‘Positive’ form portions of which are removed by intersections with Trim Surfaces.

Trims - One or more surfaces of a Trim are used (see Trim Roles, below). Portions of the Primaries that fall on one side of those surface(s) are removed.

Trim Roles - Which surface(s) of the Trim Object are used, and which side of those surfaces will be retained in the final form (ex. 'Inside Caps'). The Object Context menu (fig. 2), enables only those Roles available with Primitive type you clicked (or, if you have a selection, Roles common to all Primitives in that selection).

Active/Inactive - Cluster Property. Only one Boolean Cluster is Active a time. All of an Active Cluster’s Trim Objects are displayed as wireframes - which may be selected and modified.
Trim objects of Inactive Clusters are hidden - you only see their effect on the Primary Objects. Inactive Boolean Clusters may be selected, moved and rotated like standard GroBoto Primitives.

Primary/Trim Objects
Geometric Booleans are described by terms like; Union, Intersection and Difference. This can be tricky logic to wrap your head around. Fortunately, the GroBoto System is simplified, and fully interactive.

Key to understanding GroBoto's System is the notion of Primary and Trim Objects.

Primary Objects are your starting point. They establish the entire 'positive' form — the outer limits of your Boolean. Trims can only subtract from Primaries.

The Primary Objects in your Boolean Cluster form a Union - the combined form you've always seen with overlapping GroBoto objects. For simplicity in this example, we use a single Sphere as our Primary (the behavior would be the same if it were several Primitives lumped together).

Trim Surfaces (sidewall or 'Body' of a cylinder in this example), are intersected with the Primary. We remove any part of the Primary that falls on one side of that Trim Surface. In the 2D thumbnails (upper right in each of these figures), the white portions indicate which side we are using. The Boolean result is the area where both thumbnails are white.

This is all quite intuitive when working interactively in GroBoto — and you can flip Trim Surface sides with a simple click.
Infinite/Special Trims
Figure 1 shows what you expect to see when a Trim Cylinder set to Outside-Body is combined with a Sphere Primary Object.

Note however, that bodies of Cylinders, HyperRods, Cones, — as well as flat surfaces, like Cylinder Caps, are infinite. A boolean set up like this actually defines an infinite cylindrical trim surface that still cuts a hole all of the way through the Sphere (fig. 2 & 3).

This can be used to your advantage. Trim objects act like widgets and can be kept small and positioned where they are easier to see and manipulate. However, you can not create a pocket or crater that includes the caps of the Trim Cylinder — cutting only part way through the Sphere. This limitation of the current system will be addressed in the v3.x cycle. We will also show you some workarounds in future tutorials.
Active Editing
With Booleans toggled Off in the Scene (Toggle is in the Scene Context Menu), you see all of the Primaries and Trims of all Clusters as normal GroBoto Primitives.

With Booleans toggled On, you see the Boolean result, and the Clusters behave much like individual GroBoto Primitives when moving, rotating, etc.

When you Activate a Cluster (Activate Objects Boolean Editing - Object Context Menu), it becomes editable... Trims are displayed as wireframes, and can be dynamically edited with the Boolean result updating in real time.

Important Note: Primaries in an Active Cluster are automatically kept in a semi-selected state (they need to be selected to update dynamically). However, GroBoto keeps Primaries independent from any selected Trims, allowing you to move, rotate, reshape Trims without effecting those Primaries.

You can select Primaries, and edit them independently (without any Trims selected), but should always allow GroBoto to keep Primaries in this semi-selected state when editing Trims).

Tip: For more fluid editing with complex scenes and/or Clusters , try the 'Quick Line' mode (Scene Context Menu).
Alerts & Panels
The Mac version has a few additional Panels and Dialog Boxes that help set up, edit and manage your Clusters. They do not offer any significant functionality beyond what is available through GroBoto's Context Menus (available in both Mac v3 & Windows Betas). They are shown in some of our videos, but we will be careful to always show the same Boolean options without the use of those interface items in future videos.

The same Panels and Dialog Boxes will be added to the Windows version soon.