# About Distance and Band Analysis

 This section provides detailed information related to distance and band Analysis capabilities:

## What can you do with Distance and Band Analysis capabilities?

The measure capabilities vary depending on the license type:

In DMU-P1, you can measure the minimum distance only between products in the same selection, between products in the selection and other products in the document, or between products in two different selections, and view the results in a separate viewer.

In DMU-P2, you can, in addition, measure distance along x, along y and along z.

You can also run a band analysis to compute and visualize the areas on products corresponding to a minimum distance within a user-defined range. For example, you want to know whether there is enough space for hands around a steering wheel (no red area) as well as determine what objects can be reached while keeping hands on the wheel (green area).

The green area on A corresponds to all the points on A for which the minimum distance to B is within the user-defined minimum and maximum distance.

The red area on A corresponds to all the points on A for which the minimum distance to B is less than the user-defined minimum distance.

The two shemes below aim at clarifying the band analysis result:

#### 2D figure

The points on A for which the minimum distance to B is within the user defined distance are calculated in 3D, and the result is the area inside the cone extending from B

#### 3D Figure

A is a point, B is a sphere and D is the minimum or maximum distance.

Let's consider a = accuracy; then the green area = maximum distance +- a and the red area = minimum distance +- a

## Distance and Band Analysis Results

• Results differ depending on the sag value used.

• The Result reflects the accuracy value (expressed in mm) specified in the Edit Distance and Band Analysis dialog box and not the exact maximum and minimum distance values defined by the user.

• The accuracy value entered in the Edit Distance and Band Analysis dialog box defines the maximum value for the length of the longest side of a triangular representation of the results. This representation is used to obtain the red and green surfaces.

The default accuracy value is 5mm. The minimum value to be accepted is 0.1mm (or in Inches

0.0039).

• To obtain a more accurate result - a geometrical result approaching the exact minimum or maximum distance values - the accuracy value should be refined (be careful, the lower the accuracy value is, the longer the calculation time is and the higher is  the memory consumption).

### Sag:

The sag corresponds to the 3D fixed accuracy value for calculating tessellation on objects (3D fixed accuracy is set in the Performances tab of Tools > Options > General  > Display. By default, this value is set to 0.2 mm.
In Visualization mode, you can dynamically change the sag value for selected objects using the Tools > Modify SAG command
Note: sag is offset from the skin inwards.

## Associativity

Distance measurements are associative in both DMU-P1 and P2. If you modify one of the products (for example, move it or change the contents of a group), just run the measurement again to obtain the updated results.

## Creating Groups of Products

In DMU-P2, prior to running your distance analysis, you can create groups containing the product(s) you want to analyze using Group in the DMU Space Analysis toolbar or Insert > Group... in the menu bar.

Groups created are identified in the specification tree and can be selected from there for the analysis. Only one group per selection can be defined.