# HM-2060: Create and Edit Solid Geometry

The use of solid geometry is helpful when dividing a part into multiple volumes, for example, to divide a part into simple, mappable regions for hex meshing.

In this tutorial, you will learn what solid geometry and topology is, and what 3D topology looks like.

- Point: 0 dimensional; has only x, y, and z coordinates
- Line: one-dimensional; has length, can be curved through three-dimensional space
- Surface: two-dimensional; has an area
- Solid: three-dimensional; has a volume

This exercise uses the solid_geom.hm file, which can be found in the hm.zip file. Copy the file from this directory to your working directory.

## Open the Model File

In this step you will open the model file, solid_geom.hm.

## Create Solid Geometry from Bounding Surfaces

In this step you will create solid geometry from the bounding surfaces.

## Create a Solid Geometry Cylinder

In this step you will create a solid geometry cylinder using primitives.

## Subtract a Cylinder's Volume

In this step you will subtract the cylinder's volume from the rest of the part.

## Split the Solid Geometry

In this step you will split the solid geometry using bounding lines.

## Split the Solid Geometry Using a Cut Line

In this step you will split the solid geometry using a cut line.

You should still be in the Solid Edit panel, trim with lines subpanel.

## Merge Solids

In this step you will merge solids together.

You should still be in the Solid Edit panel.

## Split Solid Geometry with a Plane

In this step you will split solid geometry with a user-defined plane.

You should still be in the Solid Edit panel.

## Split Solid Geometry with a Swept Line

In this step you will split the solid geometry with a swept line.

You should still be in the Solid Edit panel.

## Split Solid Geometry with a Principal Plane

In this step you will split the solid geometry with a principal plane.

You should still be in the Solid Edit panel.

## Split Solid Geometry by Creating Surfaces

In this step you will split the solid geometry by creating surfaces inside the solids.

## Suppress Extraneous Edges

In this step you will suppress extraneous edges on the part.