Today, we continue with part 3 of modelling the Winton Guest House, where we will be looking at modelling the leaf building of the model.

Part 2 Recap

In Part 2, I modelled the long trailer-looking building together with its features. it didn't follow the world plane, so I had to use the surface that I created to create the base profile. Not to mention I couldn't extrude the shape because the two profiles have different orientations.

You can read more about part 2, here.

Learning Features of Part 3

• A pretty typical solid intersection workflow

• How to control arcs

Modelling

In previous parts of this model, we have only looked at directly generating the geometry for the different buildings. Specifically, when we see a building, we try to immediately generate the shape and then through some operations finalize the actual shape itself.

But with the leaf building, we have to take an indirect approach. We have to first build B-reps that represent our plan and elevation profile and then use a solid intersection to get our desired shape. Let’s see how we can do this.

1. Create Plan Profile

So, first off, we have to create our plan profile. To do this, we have to again select an edge from the central prism building and select a point.

Which roughly corresponds to the green cross in the picture below

Then, just for more plane manipulation practice, I am going to draw a line that is perpendicular to the surface instead of following the plan drawing above. This is the green line in the image below.

To do this, I can select the face from the central b-rep, evaluate the surface and then use the normal of that plane to align a world XY Plane.

Using the vectors of this new plane, I can create a point that is a certain distance away from the surface.

Then, I can use the SDL component to create a line which is the outer line of the plane profile

To get the inner line, I can then connect the origin point of the plane with an end point of that central prism edge.

I can then create an arc between the inner and outer lines. To do this, I use the SED Arc component that will create an arc-blend. All I have to do is feed in the endpoints of the lines and a starting direction.

Because the arc sits flushed against the inner line, the starting direction for the arc is the direction of the inner line.

Then, I just close off the profile and join all the curves together into one closed curve.

2. Create Elevation Profile

Then we move on to creating the elevation profile. First, we start off by getting the endpoints of our outer line.

With those two points, we can build lines in the Z direction of a certain distance. This distance will be the height of our leaf building itself.

Then, like before, we can build an arc between the two lines. But this time, we don’t have an obvious starting direction. Therefore, I want to be able to control the severity of the arc. I can do this by creating a line and then rotating it.

Creating the parametric arc

First, I create a line that is in the Z direction from one of the endpoints.

The length here doesn't matter as we are only using it for the direction. Then, I re-origin my surface plane to the endpoint and rotate my line by some angle on a slider.

Then I use the SED Arc component to create the arc blend and pass in this rotated line as the starting direction.

I can then change the severity of my arc by controlling how much I am rotating that line. All that is left is to then join all the curves and we have our elevation profile.

3. Run the solid intersection

Now with our two profiles done, I can extrude them and run the solid intersection to get our final leaf building.

I extrude the plan profile upwards and the elevation profile in the plane's normal direction to get my two b-reps for the intersection.

But because it is a solid intersection, the B-reps that I am using must be closed. So, I cap them and use the Solid Intersection to get the final shape.

Final Thoughts

And that is it! By modeling the leaf building, we have completed the entire Winton Guest House model. And I hope you can appreciate the mental shift required to perform the solid intersection.

We no longer want to directly generate the geometry, we want to build the needed construction shapes to obtain our final shape.

If you have any questions at all about the modeling or the workflow, comment below or shoot me an email at [email protected]

But we aren’t done just quite yet. All this time, I haven't been refactoring the script because I didn't want to detract away from the actual modelling experience.

If you are following your instinct and experimenting with different geometric operations to get your end result, the last thing you want to worry about is how your script looks. So, I tend to either refactor portions of my script at a time or the entire script once I am happy with the result.

So, that will be the main topic for next week’s article and it will be the final part of the Winton Guest House model.

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

Resources

The Youtube version of this Article:

To get the Grasshopper Script for this model, sign up below (if you aren’t already) :