Assigning resources with a curve

Assigning resources with a curve

Goal: put a resource on a task, with units per day and a curve that decides how those units are spread over the days of the task.

When you need this

As soon as you want to see who works where and when: the bricklayer on the outer cavity leaf, the crane on the hollow-core floor slabs. Without an assignment there is no load and so no histogram or overallocation.

Two terms. The units (in the panel the column Units, in the Assign window the field Units/day) are how much of the resource works on the task per work day: 1 is one bricklayer, 2 is two of them, 0.5 is half a day. The curve decides how the total, units times duration, is spread over the task's work days. Work is rarely even: on a wall the start is quiet, the middle busy and the end quiet again.

The outer cavity leaf takes 6 work days. With one bricklayer and the curve Uniform that is 1 unit on each of the 6 days, 6 together. With the curve Bell shaped it is still 6 units together, but the distribution becomes 0, 1, 2, 2, 1 and 0.

Steps

You can assign a resource in two ways. The resource must already exist (see Managing resources).

Via the ribbon

1. Select one task in the task list. It must be an ordinary task, not a milestone and not a phase.
2. Choose Resources › Assignment › Assign ▾.
3. In the window, fill in the Units/day (default 1) and choose the Curve (default Uniform). They apply to the resource you pick now.
4. Click the resource. The window closes and the assignment is there.

For a second resource you open the window again. Resources that are already on the task are missing from the list.

Via the Properties panel

1. Select the task. The Properties panel is on the right; if you do not see it, turn it on with View › Panels › Properties.
2. In the Assignments block, right at the bottom, choose the resource at Assign resource. The assignment starts with units of 1 and the curve Uniform.
3. For each assignment, change the Units. Click the name of the resource to show Curve, and choose another curve there.

That is also how you change an existing assignment. With the bin (Remove) at the end of the line you take the assignment off the task. The resource itself stays. With Move to… (shown after a click on the name) you move the assignment to another task.

The curves

• Uniform: the same every day. This is the default and fits work that is equally heavy every day.
• Front loaded: the start is heavier than the end. Fits work that begins with heavy effort, such as setting out.
• Back loaded: the end is heavier than the start. Fits work that gets busier towards completion.
• Bell shaped: a peak in the middle, with a quiet start and end. Fits a wall that starts quietly, is in full swing in the middle and tails off.
• Early peak: a peak before the middle. Fits work that gets up to speed quickly.
• Late peak: a peak after the middle. Fits work whose busy period only comes late.
• Double peak: two peaks. Fits work with two busy moments.
• Turtle: a quiet start and end with a broad peak in the middle. Fits long work that builds up and winds down gradually.

The curve only changes the distribution. The duration, the dates and the total stay the same. You do not need to recalculate afterwards. The histogram adjusts straight away. Choose Resources › Histogram › Histogram to see it. If you select a task, the histogram shows only the load of that task.

Pitfalls and what the app does then

A curve can push the peak above your units. With a whole number as units, the app rounds the value per day to whole units, and the total stays the same. A bricklayer with units of 1 on the outer cavity leaf and the curve Bell shaped gives 0, 1, 2, 2, 1, 0. On the two middle days that is 2 units against Max units of 1. The histogram colors those days red and the resource counts as overallocated. Choose another curve, or spread the hours yourself (see Adjusting the hour distribution). With units such as 0.5 the app rounds to hundredths. On a short task with whole units the shape therefore becomes coarse: over 10 days Turtle with units of 1 gives the distribution 0, 1, 1, 2, 2, 1, 1, 1, 1, 0, exactly the same as Early peak.

No milestone or phase. The Assign button is then disabled, and Properties says Assignments are not possible on milestones. or Assignments are not possible on summary tasks.

A resource only once per task. If the resource is already on the task, it is no longer in the list. If all resources are already on the task, the app says All resources are already assigned. If there is no resource yet, it says Create resources first (Resources tab).

The units must be greater than 0. The app does not accept a value of 0 or less.

Material. For a material resource the units are the quantity per day, in the resource's unit, for example m³. Material does not count towards the task's duration.

A task type can adjust the duration. If the task is on Fixed work or Fixed units, a second resource changes the task's duration. The schedule is then out of date; press Calculate (F5). See Task types: duration, units and work.

A distribution of its own. If the assignment already has an hour distribution of its own, the curve is disabled and shows Contour. Release that distribution first via Hour distribution….

Undoing. You can undo creating, changing or removing an assignment with Undo (Ctrl+Z).

See also

• Adjusting the hour distribution: setting the hours per day yourself.
• Resolving overallocation: what to do when a resource has too much to do on a day.
• Task types: duration, units and work: what happens to the duration when you change the units.
• Resource panel: all fields and buttons of the resource panel.
• De Vaart Apartment Complex: all five resource types, six of the eight curves and a tower crane with a capacity step from 30 August 2027.