Construct CAD Documentation

Last Updated: 2026-02-05

Construct is OctoMY's integrated 3D CAD application for designing robot parts using Signed Distance Fields (SDF).

User Guides

• Interface Guide - Panels, settings, and developer tools
• Scene Organization - Node types, tree structure, and best practices
• Material System - Managing materials, PBR properties, and CSG material blending
• Rendering Modes - PBR, Environment-lit PBR, and progressive Path Tracing
• Rendering - Tone mapping and post-effect parameters
• Undo & Redo - Shortcuts, what is undoable, batched and agent edits

Features

SDF Primitives

Create 3D shapes using mathematical primitives:

• Sphere, Box, Rounded Box
• Torus, Cylinder, Cone, Capsule
• Ellipsoid, Octahedron, Plane

CSG Operations

Combine primitives with boolean operations:

• Union, Subtract, Intersect
• Smooth and chamfer variants: Union smooth, Subtract smooth, Union chamfer, …

Transform Operators

Position and repeat geometry:

• Translate offset, Translate axis, Rotate euler (and its XYZ, XZY, YXZ, YZX, ZXY orders), Rotate axis, Rotate quaternion, Scale uniform, Scale per-axis, Mirror axes
• Repeat linear, Repeat radial, Repeat grid

Material System

Apply PBR materials to primitives:

• 20+ built-in materials across categories
• Custom material creation and editing
• CSG material blending modes

Architecture

Construct uses a data-driven architecture where primitives and operators are defined in YAML files with embedded GLSL shader code. This enables:

• Hot-reloading of primitive definitions
• Custom primitive and operator creation without recompilation (see Write a transform operator)
• Automatic parameter UI generation

Units

Every length in a Construct scene is millimetres — parameters, transforms and exported meshes alike. A display unit can be chosen on the scene root; so far only the bounding-volume readouts honor it, and every other surface still displays raw millimetres. That limit is known and deliberate for now — if a panel shows a number that looks unconverted, this is why, not a broken scene.

File Format

Construct scenes are saved as .construct files using a YAML-based DSL format that includes:

• Scene hierarchy and instance definitions
• Parameter values and transforms
• Material definitions and assignments