Today, we continue with part 2 of modelling the Winton Guest House. Where I look at creating the longer trailer building together with its features.

Part 1 Recap

In part 1, I modelled three buildings that all used similar workflows.

Each building creation process is roughly shown below:

1. Choose an edge of an existing rectangle

2. Then choose a point on that edge

3. Create a rectangle from the chosen point

4. Manipulate rectangle if need be (rotate or move a vertex)

5. Extrude in the right direction.

You can find a detailed explanation of Part 1 including the grasshopper script that I used, in last week's article here.

Learning Features of Part 2

• How to create a plane that isn't aligned with any of the world planes

• How to work with such a plane

• Get more familiar with creating rectangles using different domains

Modelling

1. Select an Edge and a Face

Like a lot of the steps in part 1, I start off by selecting a point of an edge from the central prism.

Which roughly corresponds to:

But this time, because the face of the trailer doesn't align with any of the world planes, I need to also select the right face. Through a very familiar process, I can select the face of the B-rep with the Deconstruct Brep component.

2. Create a Plane in the same orientation as the selected surface

From there, I can use the selected surface and create a plane that sits on the surface with the Evaluate Surface component.

This component works similarly to the Evaluate Curve component, instead of giving a parameter t on a curve, I have to give it two parameters in the U and V direction of the surface. More on surfaces here. Grasshopper offers a way to do this visually with the MD slider component.

But even though the plane has the correct orientation, it isn't in the right location. The origin of the plane should be my chosen point from earlier. To move the plane, I can re-define its origin with the Plane Origin component.

From here, we can go through the same steps in part 1 and create a rectangle for the trailer building.

3. Create Trailer Building

Now, if I followed the same steps in part 1, I would be looking to extrude the rectangle in a direction but this building is different. Because, if we look at the plan view of the model, the orientation of the shape does not end the way it started.

This is best represented by the two red lines in the figure below, notice how they are not in the same direction.

Just to further show what I mean, let’s see what happens if we do just extrude the current rectangle in the X-direction.

You can see that the end result is not what we wanted the building to look like. So, instead of trying to extrude in a single direction, I am going to create another rectangle and loft between the two. To do this, I have to first make a rectangle that is in the right orientation.

I then move the rectangle by some amount and then loft between the two.

You can see that by using the loft, I am able to better represent the trailer building according to the plan view of this model. With the trailer created, I can then move on to creating the other components around the trailer.

4. Create the Column

To create the column, I have to again select the right edge and the right point of the trailer building that I have just created

Which roughly corresponds to this point

Then, I can move the point a certain distance away from the edge, create a circle using the circle component and extrude it upwards to the height of the trailer building.

5. Create the container

To create the container, I have to first move the point of the circle to the top of the column. And then, like before, I will create an XY plane and rotate it.

Using this plane, I can then create my rectangle but I need to also be inclusive of the circle when I do so. To do this, I can simply include the radius of the circle when I create the rectangle. The diagram below hopefully better shows what I mean.

So if I include the negative of the circle's radius, my circle should sit inside the rectangle.

To do that, I can feed in the dimensions of my rectangle and the negative radius into a bounds component. The component will take in all the values and create the domain that I can use to create the rectangle.

Then, I can just extrude the rectangle upwards by some amount as the height to create the building

Final Thoughts

This brings us to the end of part 2. As you can see, the workflow for these buildings was quite different from part 1. It was no longer about creating the rectangle and extruding it, it became more of a problem-solving exercise of trying to get the B-reps in the right shape and orientation.

In the next part, we look at creating the Leaf structure which is the final and most complicated building of this model. So far, we have been creating buildings with extrusions and lofts but the leaf structure requires a very different approach, we have to use solid intersections.

This article belongs to a 4-part series that is about modelling the Winton Guest House in Grasshopper. It aims to demonstrate how Grasshopper is used to create models in projects.

Part 1 - Setup and Modelling

Part 2 - Modelling

Part 3 - Complex Geometry Modelling

Part 4 - Organise, Refactor and Finishing Touches

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