# Geometries

The Geometries element contains information about any geometries that are in the simulation. You can import a file, or create your own with CSG using the primitive shapes described below.

Be sure to assign a Material to a geometry object before it will appear elsewhere in the simulation (i.e. as an option for a boundary condition, particle emitter, particle absorber, etc.).

## CSG

Constructive Solid Geometry can be used to build your own complex geometry. To construct a CSG, left click on the “+” sign next to Geometries and right click on the now revealed CSG tab. Choose “Add Primitive” and select your shape.

kind (not editable)
Construction Group
tessellation

The size of triangles used to construct the shape. This is a unitless number that is the maximum deviation of a facet from the curved surface divided by the diameter of the facet.

Sphere

kind (not editable)
Sphere
material
The material to use for the shape. Chosen from a list of imported materials in your simulation.
x position
The location of the center of the sphere in the x direction.
y position
The location of the center of the sphere in the y direction.
z position
The location of the center of the sphere in the z direction.

Box

kind (not editable)
Box
material
The material to use for the shape. Chosen from a list of imported materials in your simulation.
length
The length of the box.
height
The height of the box.
width
The width of the box.
x position
The location of the center of the box base in the x direction.
y position
The location of the center of the box base in the y direction.
z position
The location of the center of the box base in the z direction.
width direction x
Set to 1 to make the width parameter of the box correspond to the x direction.
width direction y
Set to 1 to make the width parameter of the box correspond to the y direction.
width direction z
Set to 1 to make the width parameter of the box correspond to the z direction.
angle
The angle of the box.

Cylinder

kind (not editable)
Cylinder
material
The material to use for the shape. Chosen from a list of imported materials in your simulation.
length
The length of the cylinder.
x position
The location of the base of the cylinder in the x direction.
y position
The location of the base of the cylinder in the y direction.
z position
The location of the base of the cylinder in the z direction.
axis direction x
Set to 1 to make the axial direction of the cylinder x; if set to -1, the length parameter will extend in the negative direction.
axis direction y
Set to 1 to make the axial direction of the cylinder y; if set to -1, the length parameter will extend in the negative direction.
axis direction z
Set to 1 to make the axial direction of the cylinder z; if set to -1, the length parameter will extend in the negative direction.

Cone

kind (not editable)
Cone
material
The material to use for the shape. Chosen from a list of imported materials in your simulation.
height
The height of the cone.
The radius of the base of the cone.
x position
The location of the center of the cone base in the x direction.
y position
The location of the center of the cone base in the y direction.
z position
The location of the center of the cone base in the z direction.
axis direction x
Set to 1 to make the axial direction of the cone x.
axis direction y
Set to 1 to make the axial direction of the cone y.
axis direction z
Set to 1 to make the axial direction of the cone z.

Torus

kind (not editable)
Torus
material
The material to use for the shape. Chosen from a list of imported materials in your simulation.
The radius to the center of the torus.
The radius from the center of the torus to the outside of the torus.
x position
The location of the center of the torus in the x direction.
y position
The location of the center of the torus in the y direction.
z position
The location of the center of the torus in the z direction.
axis direction x
Set to 1 to make the axial direction of the torus x.
axis direction y
Set to 1 to make the axial direction of the torus y.
axis direction z
Set to 1 to make the axial direction of the torus z.

Pipe

kind (not editable)
Pipe
material
The material to use for the shape. Chosen from a list of imported materials in your simulation.
length
The length of the pipe.
The inner radius of the pipe.
The outer radius of the pipe.
x position
The location of the base of the pipe in the x direction.
y position
The location of the base of the pipe in the y direction.
z position
The location of the base of the pipe in the z direction.
axis direction x
Set to 1 to make the axial direction of the pipe x; if set to -1, the length parameter will extend in the negative direction.
axis direction y
Set to 1 to make the axial direction of the pipe y; if set to -1, the length parameter will extend in the negative direction.
axis direction z
Set to 1 to make the axial direction of the pipe z; if set to -1, the length parameter will extend in the negative direction.

TruncCone

kind (not editable)
TruncCone (Truncated Cone)
material
The material to use for the shape. Chosen from a list of imported materials in your simulation.
height
The height of the cone.
The radius of the base of the cone.
The radius of the top of the cone.
x position
The location of the center of the cone base in the x direction.
y position
The location of the center of the cone base in the y direction.
z position
The location of the center of the cone base in the z direction.
axis direction x
Set to 1 to make the axial direction of the cone x.
axis direction y
Set to 1 to make the axial direction of the cone y.
axis direction z
Set to 1 to make the axial direction of the cone z.

Wedge

kind (not editable)
Wedge
material
The material to use for the shape. Chosen from a list of imported materials in your simulation.
length1
One length of the wedge.
length2
The second length of the wedge.
height
The height of the wedge.
width
The width of the wedge. Extrudes the wedge from a two dimensional to three dimensional object.
x position
The location of the base of the wedge in the x direction.
y position
The location of the base of the wedge in the y direction.
z position
The location of the base of the wedge in the z direction.
width direction x
Set to 1 to apply the width parameter in the x direction.
width direction y
Set to 1 to apply the width parameter in the y direction.
width direction z
Set to 1 to apply the width parameter in the z direction.

## Boolean Operations

CSG Primitives may be combined in three different ways:

Subtract
This will subtract the second selected primitive from the first selected primitive. Denoted by $$-$$.
Union
This will combine the two primitives into a single object. For use if the combined object is set to be a particle sink. Denoted by $$\cup$$.
Intersect
This will leave only the volume of the two primitives that intersect as an object. Denoted by $$\cap$$.

Boolean operations may be nested, for example two primitives may be combined in a union, and then with a third primitive in a second union. To combine primitive shapes, you must first add two or more shapes to your simulation. Once your primitive shapes are added, highlight the two shapes you wish to combine and right-click and select Boolean Operation then the operation you wish to perform.

## Imported

You can import a geometry of type .stl, .ply, .vtk, .stp, .step, or .p12 by right-clicking the Geometries element and selecting Import Geometries.

kind (not editable)

• TriangSolid
• OceStepFromFile
filename
The name and location of the imported file.
scale
A factor to scale the imported geometry by. (Not available in 8.0.)
tessellation
The size of triangles used to construct the shape. This is a unitless number that is the maximum deviation of a facet from the curved surface divided by the diameter of the facet.

## Meshes

Once a shape has been created using a primative or imported, the shape will appear under the “CSG” tab if you created the shape or “CAD” tab if you imported the shape. If you want to view the mesh that is used to represent that shape in the simulation, then right click on the shape and click on create surface mesh. The mesh will be added under the “Meshes” tab. If you uncheck the box next to the shape under the “Geometries” tab, this will hide the solid shape, revealing the surface meshing used in the simulation. If the mesh is not revealed, check the box next to the shape under the “Meshes” tab. The resolution of the surface mesh depends on the resolution of the grid, which is determined under the “Grids” tab. Increasing “xCells” makes both the grid and surface mesh finer in the x-direction.