localstarlight

I have a USD of a boat, with two different options for masts in it. I want to create a variant for each. I thought maybe I could run an initial prune node (using deactivate) to get rid of one of them (so this could be the default). And then create a branch with using configure primitive nodes to turn off the default one and activate the other one, and then feed that into an add variant node.

However, when I try this, and then use set variant, it doesn't do anything. This is my first time actually using Solaris without following a tutorial so it's clear there's some basic USD stuff I don't quite understand yet.

What would be the correct way to go about building variants that are essentially different iterations of different components being activated or not?

Ah, OK, thanks for letting me know about that, I didn't realise that was an option.

That said, it's still tricky to get the sun looking correct when working with the default settings.

Here is an example of the kind of 'orbital sunrise' I am looking for:



Here is the default sun geometry from the Karma Physical Sky as seen from orbit:



I can push and pull the atmosphere parameters around to try and get something working for this particular instance, but it breaks the look of everything else, and I assume the default values for the atmosphere are based on real values for an Earth-like atmosphere.

Previously I have been doing this in Redshift, where I use an actual VDB with values ramped according to real-world values, and it works. It's slow and cubmersome because of the size of the volume, but it works. I'm hoping to replace Redshift with Karma, but we do a lot of space stuff, so it would be great if this worked as expected.

No, I’m talking about the new atmosphere model: https://www.sidefx.com/docs/houdini/nodes/lop/karmaskyatmosphere.html [www.sidefx.com]

Which is a much better atmospheric/sky model than the older Karma Physical Sky. And while the images on the documentation show it with a sun in the sky, there’s actually no sun by default.

I’m fairly sure you’re not supposed to just combine the two approaches. The nice thing about the new atmosphere is that it works from space as well. Much like the atmosphere in Unreal Engine it’s actually simulating a planetary atmosphere.

I’m just asking about the best approach to adding a sun to this very nicely physical atmosphere model.