Week 1 – Houdini Basics

Houdini is to Maya, what Nuke is to After Effects. It allows you to model using a node-based system. Whilst more complicated at first, it allows you to model complex objects much faster than in Maya.

We started off by creating a tower with a spiral staircase.

: The tube node creates a tube, we can then set the number of rows and columns the tube has. The facet node then separates the primitves from each other.

: We then use the primitive node to scale down our primitives, so there is gaps between them.

: We use the grouprange node to select every other row of bricks.

: We then use a transform node, to rotate only the group we just created.

: We then use the polyextrude node to extrude our bricks.

: To create concrete filler we extrude an earlier version of our tube. We then convert this into a vbd along with our bricks.

: We then use a vbdcombine node to find the gaps between the bricks.

: This is then converted back to polygons, and merged with our bricks.

Week 2 – Particles

In week 2 we looked at Particles in Houdini.

Using a pop-net node we can generate particles around the outline of our geometry. Then we colour the particles based on their life, using the point-wrangle node.

We then use the group node to select and delete the primitives facing away from the camera, then with another group we select the primitives at the edge of this group, to get an outline of the person.

Week 3 – Smoke

Week 4 – Bus

Week 5 – Vellum Terrain

: Creating a heightfield and applying it to a grid we created.

: Using the noise node to give the effect of mountains

: We can mask out noise and distortion modes via various methods. Like painting and masking by features.

: The painting interface

: The result

: Finally we can add colour to our mountains using the visualise node

: Our colour ramp, and colour layers within the visualise node

: The result

: Setting up a new “crest” layer

: subtracting the “crest” layer from the “eroded” layer using a VOP node

: The Result

Week 6 – Rigid Bodies

In week 6 we looked at rigid body simulation to simulate a building being knocked over.

Week 7 – Importing and Rendering

: OBJ Import

: FBX Import

: Alembic Import

: USD Import

: FBX Import using file menu

: When we import like this, we keep the hierarchy of the file

In the USD node we can select a part of geometry we want to display.

Adding a material to a usd file

Assignment 2

For the 2nd assignment we had to create a type of disaster. I chose to create a building collapse, directly inspired by a collapse that happens in the movie Tenet. This involves the building collapsing in both forwards and backwards time.

To begin I set out recreating the building in Houdini, I wanted to make this procedural so I could adjust the dimensions of the building, and the number of floors after the fact.A rather messy node tree. We only create the bottom floor of the building and then use a copy node to create the extra floors. Adjusting the sliders to change the building we’ve created. The simulation itself is pretty simple, we fracture the building using an rbdmaterialfracture node, create a group of points where we want the initial explosion to be, and then add a random pointvelocity to this group before solving the simulation with rbdbulletsolver. This simulation can then be cached and then reversed using the timeshift node, in order to get the effect we want. This reversed simulation can then be merged with a second forwards simulation in order to get our end result.