INTRODUCTION TO DIMENSIONING

Aligned dimensions

The first dimension type that we are going to look at are Aligned Dimensions. The key thing to note about Aligned Dimensions are that they can be placed between 2 or more parallel references or 2 or more points- wall ends for example. The dimensions in the image below are all Aligned Dimensions….

One important thing to note here is that when you select “Aligned” to start dimensioning, the Options bar presents you with some important choices that will aid you in creating your dimensions….

You will see below that you have a choice as to what Revit snaps to when dimensioning. The “Place Dimension” drop down box contains Wall centrelines, Wall faces, Centre of core and Faces of core.

The second choice you have when placing your dimensions are “Pick”….

At this point it is worth taking a moment to look at the differences between these two options because this is something that you will use time and again.

If we leave “Pick” set at “Individual References”, you have the choice where to dimension to, along a wall length- ie from the end of the wall to the start of the first window opening….

However, if you change “Pick” to “Entire Walls”, you can now just pick anywhere on the wall and the entire wall is automatically dimensioned….

Note that all the dimensions were added in one go, following a single click on the wall. To tell Revit exactly what elements of the wall you wish to be dimensioned, click on “Options” on the Options Bar (this is only available if you have “Pick” set to “Entire Walls”….

You will see that you can dimension (automatically) to openings, intersecting wall and intersecting grid lines. Used appropriately, this feature can save you a vast amount of time. Imagine a long elevation with 14 windows and 3 doors- and being able to dimension all of it with a single click! Ok, that’s enough of Aligned Dimensions, let’s move on.

Linear dimensions

Next on our list are “Linear Dimensions”. We use Linear Dimensions, when we want the absolute distance (measured vertically or horizontally) between two offset points. This is better explained with a diagram….

Angular dimensions

As you may expect, Angular Dimensions are used to measure the angle between two reference points that share a common intersection. Quite simply click on the first reference element (be it a line, wall, etc) and then on the second one….

Radial dimensions

Radial dimensions are used for measuring the distance from an arc to it’s centre point. In the case of Walls, you can measure either to the wall centreline or the wall face. Pressing the “tab” key when defining your dimension will toggle between wall face and wall centreline….

Baseline and Ordinate dimensions

Two other linear dimension types that are available to you (but not obviously evident) are “Baseline” and Ordinate” dimensions. These are basically two different types of “Running Dimensions”. In order top use these, you will need to first create the dimension types. This is really easy to do- just pick the default Linear (or Aligned) dimension family and duplicate it (renaming it of course). Once you have a copy of the family, you can go into it’s properties and “Edit Type”…..

You will notice that the first parameter in the list is “Dimension String Type”. This is the parameter we are interested in. If you activate the drop-down menu for this parameter- you will see that you have a choice of “Continuous”, “Baseline” or “Ordinate”. Go ahead and change the parameter to “Baseline”. This results in a dimension like this….

And if then produce a second dimension family with the “Dimension String Type” set to “Ordinate”, this is what you get….

On the face of it this looks just like a standard aligned / linear dimension. But if you look closely you will see that each dimension value is measured back to the base point of 0.

Spot Dimensions.

There are 3 types of Sot Dimensions: Spot Elevations, Spot Coordinates and Spot Slopes…

Spot Elevation dimensions

Spot Elevations are used in elevation, section, plan and 3D views to display the absolute (or relative) heights of reference points. They can also display the upper and lower height values of an element with thickness (eg a floor), in plan views.

Here is a Spot Elevation in a section view, telling us the height at the top of the wall……

And here is a Spot Elevation in a plan view. This time it is displaying the bottom and top heights of a floor plate element…..

Spot Coordinates dimensions

Spot Coordinates display the North / South and East / West coordinates of the reference point it is placed at. It can also display the elevation at that height too….

Spot Slope dimensions

And finally…….. Spot Slope Dimensions! As you might well expect, these are used for displaying the angle of slope on various surfaces and elements. They can be placed in section, elevation and plan views. Here is one being used on a roof slope in a section view…..

You have a choice of an arrow or a triangle for the symbol- we have obviously chosen the triangle symbol in the above example.