# Page 7: SphGen

Purpose: This interface is used to generate particles for SPH modeling. A number of methods are available, and here are some important notes on each:

*Box*, *Sphere*, *Cylinder*, *Cone*, and *ShellVolume*: SPH Mass = Den*Pitch^3 (where Den = User Specified Density)

*SolidNodes*: SPH particles are created at existing solid element nodes. The mass for every SPH element will be constant and equal to Vol*Den/N (where Vol = Total Volume of Solid Elements, Den = User Specified Density, N = Number of Solid Element Nodes).

*SolidCenter*: SPH particles are created in the center of each solid element, and the mass for each SPH element will be EleVol*Den (where EleVol = Volume of Each Solid Element and Den = User Specified Density).

*ShellVolume*: The body to be filled must consist of a "water tight" volume of shell element (with no free edges). However, shells normals do not need to be consistent.

NOTE: The *Fill%* option creates a "partial fill" which means filling up the body with MASS (not filling up to a specified volume percentage). So for the *SolidNodes* method, if the solid mesh is not of constant element size, it may look odd, and the density of the SPH part will not be what has been specified. For all other methods, it will fill up to the given percentage of both mass and volume.

Controls:

- Figure 1 - Create Box

- Create - Create SPH elements/nodes/parts
- Modify - Modify SPH elements/nodes/parts
*(currently disabled)*

- Method:
*Box*(other methods listed below)

- X: Enter X coordinate for min/max coordinate point
- Y: Enter Y coordinate for min/max coordinate point
- Z: Enter Z coordinate for min/max coordinate point

- Pid: Enter part ID for the SPH part
- Nid: Enter starting node ID for the SPH part
- Pit: Enter pitch (space between particles)
- Den: Enter density of the particles

- Fill%: Enter fill volume level (%)

- (User can also manually enter X/Y/Z direction for partial fill)

- Pid: Enter part ID for the unfilled particles (if needed)
- Den: Enter density of the unfilled portion (if needed)

- Figure 2 - Sphere

- Method:
*Sphere*(see Figure 2)

- CX: Enter X coordinate for center of the sphere
- CY: Enter Y coordinate for center of the sphere
- CZ: Enter Z coordinate for center of the sphere
- Radius: Enter radius of the sphere

- Figure 3 - Cylinder / Cone

- Method:
*Cylinder*and*Cone*(see Figure 3)

- X: Enter X coordinate for the base point center of the cylinder
- Y: Enter Y coordinate for the base point center of the cylinder
- Z: Enter Z coordinate for the base point center of the cylinder

- Rad1: Enter base radius
- Rad2: Enter end radius (for
*Cone*only) - Len: Enter length of the cylinder

- Polar - Generate particles in polar coordinate system

- Figure 4 - Solid / ShellVolume

- Method:
*SolidCenter*,*SolidNodes*, and*SolidVolume*(see Figure 4)

- PickPart - Activate picking on parts

- Select parts in list for operation

- Clearance - Leave gap between SPH nodes and elements (for
*ShellVolume*only)