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Custom objects

A custom mesh is a 3D shape definition stored in the mesh library — either a built-in primitive or a shape imported from an STL file. A custom object is a scene instance of a custom mesh: it references a mesh from the library and adds placement properties (position, size, rotation, layout, and material). Multiple custom objects can reference the same mesh, allowing the same shape to appear in different positions, sizes, or with different materials within a single scene. Like all objects in the unit system, custom objects repeat infinitely across the infinite array.

A semi-sphere custom object in the 3D
preview

The following primitive meshes are available by default under the “Basic” folder:

  • Box
  • Sphere
  • Cylinder
  • Semi-Sphere
  • Semi-Cylinder

Additional meshes can be imported from STL files — see Importing custom meshes from STL.

Each custom object has the following configurable properties:

PropertyDescription

Location, Determines the parent reference frame: System - Fixed (stationary),, System - Tracking (rotates with a single-axis tracker),, or Module (relative to each module).

Type, The 3D shape to use,, selected from a folder and shape within the shape library.Position, Offset from the origin of the parent reference frame along each axis (X/Y/Z).

Size, Scale of the object along each axis. A lock toggle constrains all three axes to scale uniformly.

Rotation, Rotation in degrees around each axis.

Layout, Single places one object. Repeated repeats the object with configurable spacing and count.

Transparent, When enabled the object is excluded from ray tracing and appears in the system image only.

Material, The optical surface applied to the object. See Selecting frame material for details on how material selection affects optical properties.

Custom objects in (left) 'System - Tracking' and (right) 'Module' reference
frames

Custom objects in (left) ‘System - Tracking’ and (right) ‘Module’ reference frames

When the layout is set to Repeated, the object is repeated a specified number of times with a configurable spacing in X, Y, and Z.

Custom objects arranged in a repeated
layout

Importing custom meshes from STL

Section link: Importing custom meshes from STL

Custom meshes can be imported from .stl files via the Custom meshes tab in the right panel.

The Custom meshes tab showing the File import
option

In the Custom meshes tab, select File importLoad a mesh from an STL file — then Select STL file. After loading, the default scaling and rotation can be adjusted before clicking Next. Finally, choose a folder and a name then click Import. The imported mesh will then appear under Type > Custom meshes when configuring a custom object.

The maximum STL file size is 25 MB. Only the STL format is supported — other 3D formats such as DWF or DXF must be converted to STL before importing.

After selecting a file, a 3D preview is shown. If the mesh has more than 10,000 triangles, a simplification slider appears on the preview tab so you can reduce the triangle count and see the result before importing. For best performance, aim for fewer than 10,000 triangles (approximately 1 MB when saved). Meshes exceeding 50,000 triangles cannot be imported until simplified below this limit.

See Exporting low-polygon STL files for a step-by-step guide to producing compact STL files from SolidWorks or Onshape.

A tractor modelled as a custom object in the unit
system

Each custom object includes an interactive 3D preview showing the object within its parent reference frame.

  • Toggle origin axes displays the X, Y, and Z coordinate axes of the parent reference frame (system fixed node, tracking node, or module) in the preview, helping to verify position and orientation.

Objects positioned outside the unit system bounds or more than 10 m above the system are excluded from the simulation. When this occurs, the unit system boundary box turns red and a warning is displayed in the preview.