I have learned Houdini 16.5 before, but I don’t know enough. I haven’t been able to understand Houdini’s production ideas thoroughly. At the time, I just thought it was a very powerful software, and I still didn’t understand the inner logic. Now I have the opportunity to learn again. I hope to learn Houdini thoroughly through this course.

I will record the process of learning Houdini here and try to be as clear as possible so that I can review it later.

Houdini’s software ideas are very procedural, which not only provides clear production ideas but also increases the difficulty of learning. I have studied programming for a while, and the process of learning Houdini is very similar. If you want to learn code, you must first learn its basic language, and the vocabulary of the language is a very important part.

In Houdini, there are a few main vocabularies to understand first: (Thanks Tina for sorting out, much better than what I wrote)

SOPs = Surface OPerators or geometry nodes that are inside an object folder. These are used to construct and modify geometry. Any kind of geometry from polygons to volumes.

DOPs = Dynamic OPerators or simulation/solver nodes that are used to construct simulations. Simulations read in geometry from SOPs and pass this data into the DOP solvers.

ROPs = Render OPerators in side ROP Output directories which are used to create render output dependency graphs for automating output of any type of data and for triggering external processes like rendering. Commonly used to generate sequences of geometry, simulation data and trigger Render tasks that generate sequences of images to disk.

VOPs = Vector OPerators inside VOP network nodes are used for everything from building shaders to modifying geometry, volumes, pixels, and more.

VEX = Vector Expression Language. The code language used to write shaders. VOPs are wrappers around VEX code snippets.

And there are also some operations on nodes:

There are other contents, I plan to learn the relevant and then record, the main content that I have come into contact with is these.

This week’s task is to build a wood cabin in Houdini. The operation of modeling is basically the same as other 3D software, such as boolean, extrude and reverse.

However, the Houdini node-style method allows each step to be clearly saved, and when there is a problem, you can check the problem step by step.

In this part, I am most concerned about the Delete node. It is a bit similar to the extract face function in Maya, but it is more programmatic. It can filter out what we need or don’t need through the normal value. But this is a more commonly used function.

This is the basic structure of the wood cabin:

We can build a model of the wooden board to replace this frame. Here I need to use the copy node, which can quickly copy the model and arrange it in a certain rule.

Here I also used the Polybevel node, which can increase the corner details of the model to make the model less sharp. I learned how to use this node by looking at Houdini’s official documentation. This required selecting the edge we wish to modify.

After the whole process of making a woodcabin, the biggest touch to me is the way of thinking in Houdini. When I want to make another wooden wall, I will not directly copy an already-made wooden wall like in Maya, but recreate a transform node. The model is still the same, but with different positions and sizes. Although the result looks the same as copying, this way of thinking is very helpful to me, clear and logical.

This is the wood cabin I finally made: