Animation

The animation is controlled by the stem. When it reaches a point (particle) the corresponding leaf grows. I animated the stem using a Carve SOP, that gradually trims/reveals the curve.

The leaf animation is 80 frames long, but at frame 35 the leaf is already completely shaped. From 35 to 80 it settles very smoothly while the other leaves start to grow – giving a natural look to the animation.

Using Mantra

Mantra is an amazing render engine. Like many others I don’t use it too much because for simple/medium projects it’s slow compared to RedShift or Arnold – but I love it. It reminds me of Renderman, which I used a lot, and if you start doing more complex stuff inside Houdini you’ll appreciate the great features it gives to you. In this project there are only three leaves imported as alembic cache from Maya. I then converted them to packed primitives (which in some ways are similar to Arnold standings or RedShift proxies). I then scattered them on the curve, and in the end there were in total about 130 leaves – every leaf is about 4000 polygons. When I tried to render with RedShift it took a lot to start the render – probably because it’s not optimized to work with packed primitives. I guess it has to unpack geometry before rendering and it takes time. With Mantra it’s almost instantaneous and takes a small amount of memory, so I decided to go with Mantra. The shader is very simple – I used the Principled Shader with a diffuse and a displacement map. Principled Shader is another reason why I love Mantra, so powerful and customizable (like everything else in Houdini).

Useful tutorials