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Al Whitley/3 min read

Understanding Dimensioning in Architecture and Engineering: A Detailed Explanation

Dimensioning Best Practices

Dimension to Centerlines

Common in framing and structural; clean and unambiguous.

Dimension to Faces

Finish or framing face — call out which in title block.

String Dimensions

Overall, then opening-to-opening, then detail dims stacked.

Tolerance

Note acceptable tolerances for construction.

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This tutorial walks through understanding dimensioning in architecture and engineering: a detailed explanation, covering essential tools and techniques for your projects.

Now we are going to spend a few minutes talking about dimensions, and we will use this example from above as our first topic of discussion. You can see that when we dimension, we always dimension to an object, and what we are seeing is that there are three feet from this end to that end. Now let's look at the real components of the dimension.

Again, I dimension to an object. I have an extension line that includes a small gap between the object and the extension line, which is this entity here. So it goes from the end of this object, with a small gap, the extension line goes up and extends beyond the dimension line.

So, here is the dimension line. There is an extension line here and another extension line here. Where the extension line and the dimension line meet, there is usually an indicator, which in this case is a tick mark or architectural slash.

If we look down, we can see that an arrow has been chosen instead. So, again with the dimensions, we dimension to an object. We have from where we are dimensioning, we have an extension line, another extension line.

There is the dimension line. There is the indicator, a slash, a tick mark, or an arrow, and here is the text of the dimension, which says 3 feet, 0 inches. So this would probably be an Architect's drawing because I'm seeing an architectural tick mark here.

So, you can see that I have a mark and I have the text on top of the dimension line. Down here, this is probably an Engineer's drawing, because instead of using the tick mark, they are using arrowheads. And the text is vertically centered between the arrowheads.

Both are horizontal dimensions, but if we look at this example, this is a vertical dimension. Essentially, the dimension elements are the same. We have the object, extension lines and the dimension line.

This is an architectural dimension, so we still have our tick marks or architectural slashes. The text of the dimension is still above the dimension line, but rotated 90 degrees counterclockwise. If you look at the floor plan, you will notice that the text of the dimension is always rotated counterclockwise.

When you tilt your head to the left, you will be able to read the text. This is the same if the dimension is taken from an object to the left, like here, or from the right, like here.