Advice on working with length scales

In this article, DesignSpark staff provide advice on using the length scale option within the Units settings of DesignSpark Mechanical. We also comment on the limitations of length scale in some design scenarios.

There are three length scale options available via the Units menu in File-> DesignSpark Mechanical options:

• Small (eg. millimetres)
• Standard (eg. metres)
• Large (eg. kilometres)

You can simply choose a larger unit of measurement (eg. kilometres) and it will automatically switch to the Large length scale. Switching to a different length scale will require a restart of DSM to apply changes. If you use a small or large scale, you will see an icon to confirm the scale is applied. This will be in red on the top right corner of the software window.

Important Notes:

• Length Scales of Large, Standard and Small define the maximum volume that all objects must not exceed either by original creation within DSM or by file Importing or file opening.
• If attempts to exceed the limits are made, then objects will not be created, or Move / Pull operations will fail.
• File Importing or file opening with existing objects either wholly or even partially outside of the volume will fail.

Length Scales - Space volume (max) available

Volumes are equally displaced or centred about the World Origin.

a) Small: Micrometer (µm), Nanometer (nm). Volume = 1m³

b) Standard: Millimeter (mm), Centimeter (cm), Metre (m). Volume = 1000m³

c) Large: Meter (m), Kilometer (km). Volume = 1000km³

Setting length scales: Only the new Small and XL units are referred to in this article.

The following process shows the change to a new scale from ‘Standard’ (default Install) after starting DSM.

Setting a small scale:

1. Click File > DSM options> Units.

2. Default ‘All New Documents’, select Micrometers (or Nanometers) . Click OK

3. If you click File > New > Design, an error message requesting to ‘Start a new session’ is given:

Close and restart DSM now.

4. Click File > New > Design now. A new design is opened. Note the scale (µm) is shown in DSM header.

The Units grid settings default is:

which can be changed to 1 µm

by entering 1.

Example: to make a body of length 2 µm to 3 µm using Pull.

(Annotation dimension shown to clarify the example only)

Enter 1 >

Additional information about length / distance entry and measurements, is applicable to all Scale length units:

A) Units > Primary precision setting:

Note the following on Options: Units > Primary precision setting : 6 is max setting allowed

Example: Note a Pull dimension of 0.123456789 could also be entered:

with the following result for the 6th decimal point rounded up:

The annotation dimension changes to:

B) Measuring Results precision:

Actual measuring results between opposite faces is shown below:

Note the 8th decimal point has been rounded up from 8 to 9.

Measuring results are displayed as per option setting measuring panel:

Note:

DSM Information bottom bar constantly displays XYZ or Distance or Angle measurements for one or between two selected objects ( Vertex, Curves, Faces) to the Measuring display precision setting.

Two faces >

Vertex >

Changing to a new unit from Micrometer to Nanometer whilst ‘Small’ length scale is current.

After saving (and closing) a file or from DSM start.

1. Open Units. Select Nanometers. Click OK.

2. Click File > New > Design. A new design is opened. Note the scale (nm) is shown in DSM title bar.

The Unit Grid setting (default) is: 1nm

Measurements and decimal point distance Moves or Pulls, also apply for the Nanometer unit as shown below:

Changing to a new unit from Meter to Kilometer whilst ‘Standard or Small’ length scale is current.

After saving (and closing) a file or from DSM start.

1. Open Units. Select kilometers.

2. Select OK.

3. Click File > New > Design. An error message requesting to ‘Start a new session’ is given:

Close and restart DSM.

4. Click File > New > Design. A new design is opened. Note the scale (XL) is shown in DSM title bar.

The default grid is:

Grid spacing can be changed to

with the following sketch grid unit display:

Note that within Large length scales, the unit of meter may be set.

With a default grid of

Which can be changed to mm if preferred:

Note this is still an XL scale units file capable of modelling within a volume of 1000km³.

Important note: Do not change the Unit length scales whilst in an open file.

Only the Length that is within a Scale range can be changed for ‘This Document’.