# DESIGN VARIABLES FIELD

Specifies design optimization variables field for topology optimization.

## Type

AcuSolve Command

## Syntax

DESIGN_VARIABLES_FIELD {parameters}

## Qualifier

This command has no qualifier.

## Parameters

- default_value (real) [=1.0]
- Initial constant value assigned to the design variables field.
- max_update_factor (real) [=0.05]
- Max relative step change allowed for the design variables to change between iterations.
- design_topology_interpolation (enumerated) [=simp]
- The interpolation used at the interface of the two different material regions. The two different materials are specified using the ELEMENT_SET command. For topology optimization of flow, the material_model parameter is equal to a fluid material without a porosity model, and the parameter design_material_model is equal to a fluid material model with a specified porosity model and darcy coefficient. With the material model of type fluid and the design material model of type design, representing the solid, the interface is the region between the fluid and the solid.

## Description

```
DESIGN_VARIABLES_FIELD(“design topology”) {
default_value = 1.0
max_update_factor = 0.05
design_topology_interpolation = simp
}
```