Explore the intricacies of the dimensioning process in architectural and engineering drawings, including understanding the use of extension lines, dimension lines, and the placement of measurements. Identify the differing representation styles between architectural and engineering dimensions.
Key Insights
- The process of dimensioning involves pointing towards an object and noting the space from one end to another, represented through extension lines and a dimension line.
- Architectural and engineering drawings display dimensions differently. Architectural dimensions use a mark or bar at the intersection of the dimension and extension line and position the text above the dimension line, while engineering drawings use an arrowhead and place the text halfway vertically between the arrow lines.
- Vertical dimensions follow the same elements as horizontal dimensions in architectural drawings, with the distinction of the text being rotated 90 degrees counterclockwise, enabling it to be read when tilting the head to the left.
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 towards an object, and what we are seeing is that there are three feet from the end here to the end there. Now let's look at the real components of the dimension.
Again, I dimension an object. I have an extension line that has a little space between the object and the extension line, which is this entity here. So it goes from the end of this object, with a little space, 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 mark or architectural bar.
If we look down, we can see that an arrow has been chosen in its place. So, again with the dimensions, we dimension 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 bar, a mark or an arrow, and here is the text of the dimension, which says 3 feet, 0 inches. So this would probably be a drawing of an architect because I'm seeing an architectural mark here.
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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 a drawing of an engineer, because instead of using the mark, they are using the arrowhead. And the text is located halfway vertically between the arrow lines.
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 marks or oblique bars. 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 can 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.