Render Passes for modo made easy:

Render passes allow you to create multiple versions of the same scene with different settings. With multi-layer EXR files most of the basics are covered, and generally speaking there is not as much need for render passes as there used to be jus a few years ago, however there are still plenty of reasons that you may need to use render passes. So this should give you a nice over view on how to set them up and use them. 

I'm going to make a few assumptions. First here at CoSA at the time of this writing, we are using modo 801 / 901, and we are rendering with Deadline 7.0

Here is our very important and complex shot scenario: a sphere on a plane, with a basic three point lighting.  the compositor wants each light broken out (not that uncommon), you could make three separate scenes and render each one on it's own. But then If there are changes you have to update three separate scene files and re-render them all,  it gets messy really fast. With passes all the changes track because it's all in one scene. 

In modo go to the Render layout. In the top right you should see the pass controls. The First control is Pass Groups. Click New, when the "New Render Pass Group" dialogue pops up name your pass group something appropriate. I suggest "passes." Also just to be safe make sure the the type is set to "Render Passes." This creates a group, in the groups list, called passes. 

Next, again on the Passes controls, click new to create a new pass. In this case, name it "_keyLight." Then make a "_fillLight," and "_backLight," pass as well. OPTIONAL: (IF you skip this part make sure you read about the Output Pattern templet at the end.)  Notice that the names all start with an underscore. There are other ways to do this but by adding that to the front of all your passes the name of the final rendered frame will keep to our render naming conventions. (ignore that the image above does not have this)

Now you can go to the groups panel and you can see the group "passes" with all the passes included. NOTICE that the camera icons  for all three passes are visible.  This means that all three will render when you send it to Deadline. Should you want to select which passes render (you may not always want to render them all) you can just click the camera icon to turn them off and on.  

Now here is where it gets a little complicated. Up till this pointyou have been dealing with a single scene, with a single set of settings. And every time you make an adjustment to the scene you simply make the adjustment and you're done. Now you are dealing with "overrides." 

If you go to pass groups and select "none" it's just like before you are adjusting the Base Scene. But with passes on, and one of the passes selected you are overriding the settings in the Base Scene. Well, I should say you are creating overrides, but you may not yet be applying them. But we will get to that in a moment. 

The more passes you are working with the more complex your scene becomes and if you're not paying attention, its very easy to really mess things up. So please just be extra diligent once your passes are set up. I'll have more advice on this at the end. 

Below the pass settings you will see three buttons; Auto Add / Apply / and Discard. When Auto Add is toggled on, any changes you make are applied as you make them. IF auto add is not toggled on you have to hit the Apply button to make sure your overrides get updated. You can also click Discard to set the pass back to the default.  

What are overrides? Basically any channel can be overridden. And a channel in this case refers to any value that can be animated. So you can not have an override that changes the order of shader tree items, But you could override any value to any material, shader, visibility, or color. once you have made an override you can find a list of them in the passes group.  

The override it's self is an item in the passes group, once you have set up a few you can go to the passes Pass Group and there will be a channels item, and in there you will find all the overrides. By the way I almost never bother with this on a day to day basis, but you know... just in case. 

Setting the Over rides. Back to our scene, select the key pass from the pass controls, then turn off the fill an back lights. Now go to the fill light pass, and turn off the key and back light.  And finally go to the back light pass, and turn off the key and fill. now save your scene. If you switch from one pass to the other, and have the PBR open, you will see each pass has one light on. and you can now render your scene. 

Submitting for render: you set everything up exactly the same way you normally do, with the small exception of the Pass Groups field. Just type the name of your pass group here and you are done. Also, as long as you always name your pass group the same thing, deadline should remember this and you never need to worry about it again.  There is just one last thing to be aware of. and that is the Output Pattern templet. This determines the way the pass renders will be named. it's fine by default, but if you want to change it this is where you do that. You can do things like add an underscore or periods, or even your initials if you want. But, like I said it's probably just fine by default. 

TL;DR REVIEW: 

1.) Click New under pass group to set up a new pass group.

2.) Click New under passes to set up a new pass. 

3.) When making over rides for your passes, make sure you toggle Auto Add on, or click Apply after your changes have been made. 

4.) Click Discard to reset all overrides for that pass. 

5.) Save and submit to deadline. 

6.) Make sure the name of your pass group is in the submitter.