Discover the importance of accurately transferring elevation heights between different views when constructing a 3D model, specifically applied to roof designs. This article discusses the methodology and tools applied in Autodesk's AutoCAD software to project data from one view to another, ensuring your 3D model is an accurate representation of your design.
Key Insights
- The article emphasizes the importance of accurately transferring elevation data between different views. This is particularly significant when modeling complex geometries like roofs in 3D modeling software such as AutoCAD.
- A turning line is a useful tool when projecting data from one view to another. This line, which always represents half of the total angle between two views, is used to align datums, ensuring geometry carried across from one view to another matches up correctly.
- Construction lines, horizontal and vertical lines, and fillets are among the tools mentioned in the article that aid in the accurate transfer of elevation data. These tools help to locate and represent different elements of a 3D model, such as the roof's top, fascia board locations, and the start and stop points of the roof.
This lesson is a preview from our AutoCAD Course Online (includes software) and AutoCAD Certification Online (includes software & exam). Enroll in a course for detailed lessons, live instructor support, and project-based training.
In this video, we will begin to add our geometry to our front and back views. Let's zoom in on this section of the drawing so we can have a quick discussion.
We just mirrored the left-side roof onto the right side of the drawing above, but now I'd like to get the same datum information to my front view. I know that the roof here looks fundamentally different. We're looking at the roof from this side, so we won't see the fascia boards in this orientation.
Instead, if you check the handout, we'll see a flat plane—more like a rectangle—because the roof is sloping toward us. So how do we get the data from this left elevation onto this elevation? We could use things like Copy with Base Point and potentially change our active view, but that would bring this elevation data onto this view directly—and that's not what I want to do here.
Instead, I just need the elevation heights. How tall does this roof go? How tall does this go? How tall does this go? Those are the questions I need to answer. So let's focus over here on the back view and the left view, because if you check your handout, the back view is more simple.
It is a straight line across for the fascia board and then a line across the top of the roof. These are three datum points we need to bring over—and we've already drawn them. Here is a point, here is a point, and the very top of our roof is a point.
Learn AutoCAD
- Nationally accredited
- Create your own portfolio
- Free student software
- Learn at your convenience
- Authorized Autodesk training center
To bring this data over into the back view, I want to utilize a Turning Line. This is used when we need to project our data from one view to another view, as long as we align the Turning Line. What do I mean by that? Well, follow along with me.
I'm going to go to the Home tab. I'm going to select my A-NOPLOT layer. Let's go Draw > XLine (Construction Line).
I'm going to set H, Enter, to establish horizontal lines. Now, I'm going to pick on both my Top of Plate and my finished floor Endpoints. Enter to say I'm done.
Enter to go back in, and this time I'm going to do V, Enter, for vertical. Once again, I'll grab my Top of Plate here and my finished floor line here.
Enter to lock it in. Now, you can see we've created a square. This is not the final geometry we are going to use.
Instead, I'm going to come over here, turn on Intersection, and I'm going to draw a Line from this point to this point. Enter to say that I'm done. Select your Construction Lines and delete them.
So you're left with a simple diagonal line. This diagonal line will always be half of the total angle between your two views. Because this is a 90-degree rotation, this is a 45-degree line.
Now, I'll zoom in on this line, select it, click the grip to make it hot, right-click, Scale. When I stretch this, it scales the line. I'm just going to type in 3, Enter.
It doesn't really matter how long this line is, but I wanted to make sure that it's above my highest bit of geometry and below my lowest. Now we can see an interesting phenomenon: because this line was aligned using datums that we knew would be exactly the same on each drawing—that was our finished floor and Top of Plate—any geometry that's carried across will be able to turn and match up with geometry on the other view.
Let's test that out with the ground line. I'll go Draw > XLine, H, Enter for horizontal. Here, I'm going to grab my ground line. Enter to say I'm done.
Enter to go back in, V, Enter, for a vertical line. Instead of grabbing my geometry up here—because I know it already exists—I'll find the Intersection here.
Click, Enter to say I'm done. Now this line will line up exactly with the ground line. And you can see how we might use this workflow to bring over geometry when we don’t know where it's going to go.
So let's delete these two lines and do this with our three datums. I'm going to change my current layer to A-HEAVY. Okay.
Then I'm going to go Draw > XLine, H, Enter. I'll grab all three of these points. That is the top here, and then both points here and here.
Enter to lock it in. Enter to go back in, V, Enter. Now I want to turn these lines up the drawing.
So I'll choose this Intersection, this Intersection, and this Intersection. Enter to say I'm done. Now we've turned these up the drawing.
Let's go to the View tab and change our active view to the Back. Now we can see these lines are coming across in the appropriate locations, which are the datums for the top of the roof and these two fascia board locations. All we need now is where the roof starts and where the roof stops.
We can bring those down using our datum on our Floor Plan. I'll go back to the Home tab, Draw > Ray. Turning on Ortho (F8), click, Enter to say I'm done. Enter to go back in.
And here, down the drawing with Ortho on, click. Enter to say I'm done. Now we can delete these three lines. We're left with just our roof geometry.
You can see exactly how this is going to come together. Right here in the middle is our roof. We can do all of this with Fillets—so follow along with me.
I'll go Fillet, make sure my radius is set to 0, and I'll go M, Enter for Multiple. I'm going to go across the top first: here to here, here to here. Next, I'll get the top of the fascia board by zooming in and selecting this yellow line to here.
I'll do the same over here—the yellow line to here. Remember, Fillet can also extend our lines. We'll extend these by going here to the bottom yellow line and here to the right.
Enter to say that I'm done. Now we need to Trim out our wall geometry just like we did on the left and right views. You do not need to Trim out this geometry—these are just placeholders. We'll come back to those later.
So I'll go Trim, T, Enter to select my cutting edges—just this bottom line. Enter to lock it in, and then I'll zoom in and click here and click here.
Enter to say that I'm done. All right. Control + S to save.
We have finished our roof on the back view. Now we can do the roof on the front view, and you'll see here that the geometry is going to be a little bit more difficult. We have a short overhang and a long overhang, and the long overhang will go slightly lower.
So let's Zoom Extents, Control + S to save, and in the next video, we'll talk about a good workflow for creating that roof. I'll see you in the next video.
