Rhino 2D
Module Summary:
In the last module, we took an introductory tour of the Rhino interface. Now we're going to get comfortable with the software by developing a model of an existing building. In this module, we'll be drafting 2D geometry to use as the basis of our 3D model.
Modeling a Project
For the rest of this sequence, we'll be constructing a digital 3D model of the Casa Bahia Azul in Chile, designed by Cecilia Puga.
The geometry of the project is pretty straightforward, so it's a good place to start. Once we have our model built we can use it to create architectural plans, sections, and perspective drawings.
Drawing in 2D
The first thing we need to do is find scaled drawings to base our model on. Here's a plan of the ground and second floors of the house:
I've also found this more diagrammatic set of plans that describe the design logic of the building:
And a PDF which includes a more detailed plan, as well as three sections:
This is a jpeg (raster) version of the drawing, but what's nice about the PDF is it has vector geometry which we can import directly into Rhino. The original file can be found here.
I also found these isometric drawings. We won't use these to draft from, but they could still be a useful reference. Download all the above drawings so that you can put them in your Rhino model.
It's good to have photographs to clarify any parts of the building we're finding hard to reconstruct from just the drawings. A gallery of this project can be found on the architect's website.
Starting the Model
Now let's jump into Rhino. Create a new file: since the project is designed and built in a country that uses the metric system, we're going to use the "large objects, meters" template.
Next, we'll import our reference drawings into the model. Create a new layer, name it "Picture," and make it the active layer by double-clicking on it. Then maximize the Top viewport by double-clicking on the name.
The Picture command creates a flat surface with a bitmap image applied to it. Type "Picture" into the command prompt, select the file of the first plan, then follow the prompts to place it in the model, in top view. Don't worry about the size for now, we'll correct it later. Repeat this for the other two image files.
For the PDF, since we want to bring this drawing into Rhino as geometry rather than an image, we'll use the Import command instead of Picture.
Scaling the reference drawings
We need to scale our reference drawings so that their dimensions are accurate in our model. Usually this is done by referring to a graphical scale: a symbol whose size is marked, allowing us to find the dimensions of everything else in the drawing. In all of the reference drawings we found, there's only one of these: it's on the site plan, in the page of diagrammatic plans and elevations. This is what we'll use to find out how big our building is.
This site plan is at a different scale than the rest of the drawing, so we want to isolate it before resizing it. Since this picture is an ordinary Rhino surface with the drawings applied as a material, we can do this using the Split command. Draw a rectangle around the site plan, and use Split to cut it out, following the command prompts at the top of the window. You can delete the splitting rectangle when you're done with it.
The site plan is now its own surface. Move it out of the way of the rest of your reference drawings, zoom in on this part of the graphical scale, and use the Scale command. Click on each end of the graphical scale (using the entire scale will produce the most accurate results), type '20' and hit enter. The image will then be resized so that the distance between the points you chose is 20m.
Now we can use the site plan to measure our building. While you're drawing a line Rhino displays its current length in the bottom left of the window, which is a quick way to measure distances. Try finding the length of the northernmost building module this way:
You should find that it's about 13 meters (if it isn't, use the same method on the drawing's scale to check that it's the right size). The low resolution of the image makes the plan pretty blurry, though, so it would be good if we could give ourselves some more confidence in this number. Let's look at the rest of the drawings on the page we cut this site plan out of, in particular the diagram in the top left.
This is a very useful drawing! It lays out the logic and vocabulary which govern the design. There's a standard profile (the "house" shape), and three opening sizes which are cut out of it (the gray rectangles). In plan, the module is divided into eleven equal bays, which alternate between solid walls and openings. The drawings on the right side of the page explain how three variations on this prototype are developed into the three volumes of the house.
Without these drawings, we might have approached our 2D drafting by simply tracing what was drawn in the plans, line by line. But when reconstructing a project, it's important to keep in mind that a building is not a heap of unrelated bits of geometry. Parts and dimensions will repeat. Elements will align, or be symmetrical. Often the whole thing will be laid out according to a regular grid system. The logic will differ in kind and degree depending on when and where the project was built, and by whom, but trying to uncover it, working from the abstract to the concrete and the general to specific, will leave you with a better model and a deeper understanding of the project.
So. Resize this drawing (using Scale) to make the length of the plan 13m, like it was on the site plan. How long does this make a single bay? 13 ÷ 11 is an irrational number, which seems like an unlikely choice for a module of a rational floor plan. But it's roughly 1.18. You can verify this by drawing a line in Rhino and seeing how long it is. It seems more likely that each of these bays is a much cleaner 1.2m, making the entire plan 13.2 meters long. Rescale the plan to match this number, and you'll find that other key dimensions are nice round numbers as well.
These are the dimensions we'll base our model on, so re-scale the other floor plan to match (note that, as explained in the diagram drawings, one of the volumes has an extra bay added on). You can also rotate it to be the same orientation as the diagram. We won't use the isometric or imported vector drawings for the rest of this 2D drafting tutorial, so you can move those out of the way, or select them and use the Hide command (bring back hidden objects with Show). Then we'll be ready to start drawing. If you haven't already, remember to save your model!
Drafting the Base Modules
Create a new layer called 'Grid,' give it a color to distinguish it from other layers, and double-click on it to make it active. Then lock your 'Picture' layer by clicking the icon of a lock next to it in the layers panel, to avoid accidentally selecting or moving your reference drawings as you're working.
Draw the outline of the floor plan, using the Rectangle command and clicking the bottom left corner. Since we want our dimensions to be round numbers, we'll type them in directly instead of completing our rectangle with the mouse. So type 5 for the width, hit enter (or spacebar), and then 13.2 for the length, followed by enter again.
Next we'll add the lines to mark the bays. Draw a Line along the bottom of your rectangle and then select it. To make a series of equally spaced copies of an object, use ArrayLinear (there's also an Array command, which creates three-dimensional grids of objects), following the command prompts to create 11 copies spaced 1.2 meters apart.
Now move on to the house-shaped section at the top of the drawing. Use Polyline to draw the bottom and sides, still entering dimensions with the keyboard rather than mouse (the side walls are 3m high, the width still 5m).
For the roof, it's the angle that's a round number, at 30° (check this yourself with the Angle command, following the prompts). So draw a horizontal line between ends of the side walls, and then rotate it 30° around its left endpoint.
Now Mirror the line across the floor's midpoint, Trim the lines so they meet, and Join all five segments into a single closed polyline.
To give thickness to the wall in both plan and section, Offset the outlines the thickness of the wall (0.2m).
Our last task on this part of the diagram is tracing the gray rectangles which represent the openings in the volumes.
Adapting the Prototype Plan
Next we'll take these elements and develop them into specific plans and sections of each part of the house. We can skip straight to the final diagram on the bottom right of the page.
Start by using Copy to place your base drawing onto each of these floor plans. The first two already match, but the third (the guest house) has a couple modifications.
First, this plan is one bay longer than the other two. To stretch it, select the two rectangles representing the outer wall, and press the F10 key (or use the PointsOn command). This lets you directly edit the 'control points' which define a NURBS object, and works on surfaces and solids as well as curves like these (we'll go into more detail on NURBS and control points in a later tutorial). Select the top corners of your rectangles and move them up the width of one bay, either by typing the distance or using one of the existing bays as a reference to snap to. Then fill in the missing grid line with Copy.
The other change is this third plan has a variation on the grid used in the other two. These new lines are midway between existing ones, except the topmost one, which looks to be 0.3m off (a quarter of a bay). Add these lines to the plan by copying existing ones.
We'll also adapt our cross-sections to each of these modules, so bring copies of that over here as well. This time it's the middle drawing that needs to be modified. Flip this section upside-down (with Rotate, or the Gumball), and line it up again with the underlay drawing.
Now we'll add the floor to the section. Start by drawing a line connecting the inner corners, and then copy it downwards the thickness of the floor, which looks to be 15cm. We could clean this up using Trim and Join again, but there's a useful command called CurveBoolean which allows you to extract closed regions from a network of intersecting curves. Try it out with your walls and floor, selecting the option that deletes all your input curves, since you won't be needing them anymore.
Completing the Plans
We're finally ready to move our line work over to the real floor plans of the house. Make sure when you do that inside edges of the ground-level volumes are aligned, and note that the gap between them is the width of a single grid bay (1.2m). The upper level floor plan off to the left aligns with the grid of the lower volumes.
That leaves the exterior spaces of the building to draw. You can do this using the Rectangle and Polyline commands like we did above, keeping points aligned and making sure stair treads have a consistent depth (the long ones are 0.9m, the short ones 0.3m). It would also be good practice here to keep your layers organized, creating a "Wall" and "Terrace" layers in addition to "Grid," each with a distinct color. When you're finished, you should have this:
I've made the underlay here semi-transparent to make it easier to see what I've drawn. You can do this by selecting it and going to the "Material" tab in the "Properties" panel, then moving the "Transparency" slider.
A couple other things to note. First, we haven't recreated the plan as it appears in our source drawings. Instead, we've created the reference geometry that will help us build a 3D model of this building. Don't worry if you can't picture how this is going to work yet, it should become clearer once we move into 3D.
Second, we haven't drawn any of the house's interior. These tutorials will only walk you through creating the exterior of the building, but will teach you almost everything you need to model the inside as well, so you should definitely give it a shot for some extra practice (it will also give you a lot more to work with when you start using the model to make drawings). If you'd like some more practice working in 2D before moving to the next tutorial you can start now, but doing the 3D portion of this tutorial first will give you a better idea of what geometry you'll need to complete the model.
