When using the compute mass mode, very light objects with a mass of 1e-5, 1e-6, connected by constraints, can have problems. For example, a rope is pulled to the floor under the influence of the gravity of an object at its end.
This is corrected by manually setting the mass to mass = 0.01, for example.

If you set the flipbook session label in the form of a number and text, then when you change this number, a new mplay instance is not created.
At the same time, if you use only numbers, it works correctly.
Therefore, it is advisable to start the session label with text and, if necessary, end with numbers.

To calculate the crop mask in the camera, a primitive bounding box is used. Therefore, the object used as a crop mask in the camera must have primitives. Otherwise, it is ignored.

If you need to lighten a dense volume, then you can reduce the shadow density scale in the shader.

Do not use 16-bit float for position attributes, which can have values significantly different from 1:

With high probability, the shop_materialpath attribute on points no longer works.

When creating attributes of type string in python, they are not initialized with default values. Therefore, you must first create an attribute, and then set the value to it:

node = hou.pwd()
geo = node.geometry()

geo.addAttrib(hou.attribType.Global, 'newAttribName', '')
geo.setGlobalAttribValue ('newAttribName', 'newAttribValue')

When using volume procedural (for example, for gridless advection), the resolution of the container becomes equal to 100 voxels along each axis. Therefore, volume quality must be increased:

volume quality =  (size along a larger dimension) / 100

This value is best set on the object.
If the rendering takes too long, you can create a multiplier for volume quality and reduce its value by a couple of times.

In volume procedural, you can use VDB, but you need to do vector split. The results of working with VDB and volume are almost the same.

Also in volume procedural, you can increase octree divisions. This eliminates the need to calculate empty areas. A value of 64 is sufficient; large values will take a long time to prepare before rendering.

The effect of the Z-Importance value on render time and on the image quality of the ocean with displacement:

Decreasing the Roughness parameter decreases the maximum amplitude that anti-aliased noise can generate.