• Append a Light Mixer LOP to your LOP chain.

On the left of the interface you will see a list of lights.

• Drag a light from the left side to the right side. You can now adjust the light from the slider.

  • The “null” and the “star” icons are “disable” and “solo” respectively.

  • You can adjust the brightness and/or exposure using the sliders.

• You can drag lights out of the right side of the interface, (or use the “X” button at the top), at will. This does not delete the light(s), it just removes them from the Light Mixer.

Let’s create a collection.

• CTRL click on all of the lights with “Rim” in the name.

  • RMB → New Collection from Selection

  • Name this “rimLights”

You will now see a collection in the left side of the interface. You can drag this collection into the right side. By default, the lights are ganged, and you have one control for them all. If you want, expand the collection and adjust individually.

Let’s create a collection procedurally. It would be nice to automatically include any light with the word “rim” in it in a collection.

• Delete the Light Mixer LOP, (or delete the “rimLights” collection you already have in the current Light Mixer LOP.)

• Add a new Light Mixer LOP (unless you did not delete the old one.)

• Prepend a Collection LOP to your Light Mixer LOP.

Add another Collection LOP:

Now go back to the Light Mixer LOP. You should see the two collections in the left side of the interface. !f

At this point, you may have a long string of lights in your LOP network, or lights scattered all over the place. Here are some options to help you manage the network.

• 1) Keep the lights in-line, but all in one place.

• 2) Use a Sublayer LOP to organize the lights.

  Sublayer Type

  Sublayer Inputs

If you look in the viewport, you will see a drop-down that allows you to choose which AOV to view. Of course, you may want more or less AOVs than are shown by default. Let’s edit the AOVs for all shots.

• In your LOP chain, add a Karma Standard Render Vars LOP and don’t connect it to anything yet.

• In the “LPE” section, choose the AOVs you would like to output.

• Plug this into the second input of the existing Karma Render Properties nodes.

  • In the Karma Render Properties nodes set:

  Import Secondary Input Render Vars

  On

Since we already have set up our /Render/rendesettings primitive where are render settings are stored (look for it in the Scene Graph Tree), we don’t want to stomp on the values with another Karma LOP. We are going to use a USD Render ROP to render to disc.

• Append a USD Render LOP.

Let’s create a USD Render LOP to do quick test renders.

• Copy the existing USD Render LOP.

• Rename it “quick_render”

• Prepend a Rendersettings LOP.

  • In the “Standard” tab, turn all options to “Do Nothing”

  • In the “Karma” tab:

    Primitives

    /Render/rendersettings (You can drag this from the Scene Graph Tree.)

    Action

    Edit

    Pixel Samples

    4

    Set or Create

    Set or Create

• For the bounces/limits/motion blur controls, there are Render Geometry Settings LOP and Render Settings LOP which control this behaviour. Standard USD inheritance models should work for the geometry settings.

• Also note, that for motion blur, you’ll likely have to use a Cache LOP to make sure Hydra has enough knowledge about adjacent frames.

• To use render regions, hit SPACE + 5 to jump into the Image Viewport. Marquee-drag (LMB click-drag), to create a render region. This feature is undergoing development at this time.