Developing a portfolio of CGI fluid and pyro simulations in Houdini 16.

Sourcing the Boat Geometry

While I would really like to 3D model a medieval galleon in Blender for my shot, this project is focussing on the simulation of fluid and fire in Houdini and therefore would not be a viable use of the limited time I have – I therefore found a royalty free model online.

At first I struggled to find the type of ship of wanted to use, the majority of models available under creative commons were sailing boats and dinghies. I looked at a couple of sailing ships as back ups however eventually was able to source a realistic looking model of a caravel that resembled the Santa Maria (the ship Columbus sailed to America) from

This model, while realistic, seemed to have a relatively low poly count around the hull and sails so before I brought it into Houdini I tried to open it in Blender to subdivide some of the faces so that later my collision geometry could be more accurate. Here I encountered my first problem, the file downloaded was a .3ds file designed for 3DStudio and when I tried to import the file into Blender it would not open. I therefore first had to convert the file to a .obj, a simple process that just required me to download a file converter.

With my file newly converted I brought it into blender and subdivided the hull and sails so they had double the polygons of the original model the exported it twice. Firstly back to a .obj, but also to a .ply, these different file formats hold different information primarily .ply hold normal, colour and texture coordinates. I imported both files into Houdini to compare the two and it became clear which I should use. Because Blender swaps the Y and Z axis so that the vertical plane is the Z axis, when imported the .ply file the object was pointing in then wrong direction as the coordinates had been imported from the Blender file. I therefore used the .obj file.

From here I only encountered 1 other issue with my boat file when I brought my project in to the university computers to be rendered. After transferring the files over to the new pc I opened my Houdini project and the boat file would not import. I tried a few methods to fix it and it became clear Houdini was unable to read the .obj file. Fortunately there was an easy fix, using the Houdini “Shell” function using CMD line prompts I was able to get Houdini to convert the file from a .obj to a .bgeo which is the default file format Houdini uses to import data. When I tried to import the geometry after that it worked perfectly.


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