Generate a sweep¶

Bramble can fill a Map's Attitudes table for you from parameter ranges, instead of you typing each row. Choose Full Factorial for a grid, Optimised Latin Hypercube for a space-filling design, or Linear Sweep for a single line through parameter space.

Before you start

Generating replaces every row in the Attitudes table. Generate first, then add or edit individual rows.
The generator has one column per default parameter, plus the Optional Parameters ticked in the Map. Tick any optional parameter you want to vary, such as Corner Radius, before you open the generator.
Set Map Units first. The generator's inputs have no unit labels, and values are read in the current Map Units. For example, with Map Units on mm, enter a ride height of 30 mm as 30.
You can't generate a sweep in a Map with locked Attitudes. Copy the Map instead.

Generate the Attitudes¶

Create a Map, or open an existing one with the pencil icon on the Maps page.
In the Attitudes panel, next to Map Configurations:, click Full Factorial, Optimised Latin Hypercube or Linear Sweep.
In Map Generation, fill in a column for each parameter you want to vary (see the sections below). Leave the other columns blank.
Click Generate Map. If it's disabled, hover over it to see the first problem.
Check the new rows in the Attitudes table. Rename them if you like, then click Save. Nothing is saved until you do: Cancel discards the generated rows.

What you get¶

Names: the rows are named Attitude 1, Attitude 2, … in the order they were generated.
Rounding: values are rounded to 3 significant figures. For example, a ride height of 0.03567 becomes 0.0357, and a velocity of 55.55 becomes 55.6. If you need more precision, edit the cells afterwards.
Blank columns: generated rows only hold the parameters you filled in. At run time, a blank default parameter takes its value from the Kinematic Setup's Default Ride Parameters. A blank optional parameter uses the kinematic model's own default, for example a Corner Radius of 0 (straight flow). See create a Kinematic Setup.
Maximum 50 Attitudes per generation, for every method.

Full Factorial¶

Makes equally spaced points for each parameter and combines them into a grid, so every combination is simulated. For example, Velocity with From 50, To 70 and Number of Points 3 gives 50, 60 and 70.

Input	Notes
From	First value
To	Last value. It can be lower than From, to sweep downwards
Number of Points	A whole number. More than 1 when From and To differ. Exactly 1 when they're equal, which fixes that parameter at one value in every row

Fill in all three inputs for a column, or none.
Fill in at least one column.
Total Attitudes = the product of Number of Points across the filled columns, up to 50. For example, 5 ride heights × 3 yaw angles gives 15 Attitudes.
Order: the leftmost filled column changes slowest and the rightmost fastest. With Front RH at 3 points and Yaw at 2, the rows are (Front RH 1, Yaw 1), (Front RH 1, Yaw 2), (Front RH 2, Yaw 1), and so on.

Optimised Latin Hypercube¶

Makes a random set of Attitudes that spreads evenly through the ranges you set. It needs far fewer Attitudes than a Full Factorial grid over the same ranges, which makes it a good choice for an aero map.

Input	Notes
From	Lower limit. Must be less than To
To	Upper limit
Detail Level	A whole number from 3 to 30 (default 3). Sets how many Attitudes are generated per varied parameter

Fill in both From and To for a column, or neither.
Vary at least two parameters.
Total Attitudes = Detail Level × number of varied parameters, up to 50. The cap limits the Detail Level you can use: up to 25 with two parameters, 16 with three, 10 with five.
Each parameter's range is covered from From to To, with both limits included.
The design is random. Generating again gives a different set of Attitudes.

Choosing a Detail Level

Around 5 is typical. 10 gives a dense design, and is possible for up to five varied parameters.

Linear Sweep¶

Makes equally spaced points along one line from the From values to the To values. Every filled column moves together, so it isn't a grid: with Front RH and Rear RH both filled, each Attitude changes both. For a grid, use Full Factorial.

Input	Notes
From	Start value. Must be less than To
To	End value
Number of Points	A whole number from 2 to 50 (default 4). This is the number of Attitudes

Fill in both From and To for a column, or neither.
Fill in at least one column.

Error messages¶

Message	Meaning
`Variable <parameter> is missing a value`	A column is only partly filled in
`At least 1 parameter column needs to be filled`	Full Factorial or Linear Sweep with every column blank
`At least 2 parameter columns need to be filled`	Optimised Latin Hypercube needs two varied parameters
`Maximum number of attitudes exceeded`	The settings would give more than 50 Attitudes
`Number of points must be greater than 1 for variable <parameter>`	Full Factorial: From and To differ but Number of Points is 1
`"From" must not equal "To" for variable <parameter>`	Full Factorial: From equals To but Number of Points is more than 1
`"From" must be less than "To" for variable <parameter>`	Optimised Latin Hypercube or Linear Sweep: the range is the wrong way round
`Failure to Generate Data`	Bramble couldn't generate the Attitudes. Try again, or contact support@bramblecfd.com

Run the sweep¶

Use the Map in a Run as usual: see create a Run. For sweeps of an existing design, such as an aero map, the New Attitude Checks template usually suits. See configure pre-checks.