one part black in clown pass?

[andy.engelkemier]

Is this a bug, or just a random occurrence? I like to keep my clown pass colors within a certain range. I'd prefer the colors start at R, G, B, then get equally divided from there so the colors are always as far as possible from each other. I usually get things like pink realy near another pink, on top of purple, with a really similar color next to that, etc.
But just now I got a part that rendered fine, but the clown pass made that part black, so it's pretty much good for nothing, since it's not surrounded by other parts.

Is there a way to Only render a pass? That'd be a great feature just so you don't have to waste time on a render you already have. I'm hoping rendering again gives me a new pass, otherwise I'll have to use the render layers to get that material.

[Rex]

Andy,

If all you need is a clown pass try this:

- Duplicate model and hide original
- Right-click on duplicate in scene tree and go to material>change material type and select "Flat"
- Now you can control the colors manually and render out much faster
- Using Advanced Control render output you can increase anti aliasing for better edge quality

[andy.engelkemier]

That Is a great tip, and one I've been using for years. However, the time it takes to do that on a complex model is still quite high.

Maybe add that to the wishlist; the ability to render out a pass, but not the beauty pass. The reason would be someone finished a render, then realized they need to make one small change. I want to make that change as quickly as possible. If I don't have a method that is faster than me just manually selecting the part in photoshop then I should probably just manually select the part in photoshop.

I'd love to have access to the colors in the clown pass via code though. I'm not sure how it chooses them.
I would also like an option to have a clown pass based on object, not material.

Here's a cool example with that. I can render out a few images (this would be a cool tool for you guys) of one product. A nice black gloss, and mostly matte, white gloss and mostly matte, Mid grey gloss, and mostly matte, metal chrome-like, and metal satin finish. And a clown pass with all the parts separate.
With those all as layers in photoshop, you can mockup Most objects as long as they don't have transparency. This is great for CFM exploration. Once you decide on a couple, Then you can render out nicer images of them.

[Rex]

That Is a great tip, and one I've been using for years. However, the time it takes to do that on a complex model is still quite high.

Maybe add that to the wishlist; the ability to render out a pass, but not the beauty pass. The reason would be someone finished a render, then realized they need to make one small change. I want to make that change as quickly as possible. If I don't have a method that is faster than me just manually selecting the part in photoshop then I should probably just manually select the part in photoshop.

I'd love to have access to the colors in the clown pass via code though. I'm not sure how it chooses them.
I would also like an option to have a clown pass based on object, not material.

Here's a cool example with that. I can render out a few images (this would be a cool tool for you guys) of one product. A nice black gloss, and mostly matte, white gloss and mostly matte, Mid grey gloss, and mostly matte, metal chrome-like, and metal satin finish. And a clown pass with all the parts separate.
With those all as layers in photoshop, you can mockup Most objects as long as they don't have transparency. This is great for CFM exploration. Once you decide on a couple, Then you can render out nicer images of them.

Totally agree with you. We are looking forward to making improvements to render layers and passes in the near future. I will keep this in mind and may ask for feedback during the design process.

[Speedster]

The "Auto-Clown" is a great feature, but can be somewhat arbitrary.  And for me the auto-selection is usually very, very close to the adjacent color, to where I have to set the PS selection at 1-5 % just to separate them.

So now, for critical rendering, I always make my own clown, from a special "clown" flat color library.  I duplicate the model, unlink all, then apply the clown colors to suit.  Like green against pink against blue.  You know the drill.  Then I render the beauty shot followed by the clown model shot, both with the camera locked.  I do this for each viewset or camera in turn.  Don't rely on the viewset alignment accuracy.

Yes, it can take a little more time to set up, but can save a LOT of time later in post, usually well worth the time savings offset.

Also, sometimes you just screw up and have the same adjacent color on two different materials you want to select.  So I just go in with a 1 pixel brush and erase or paint a dividing line to create the required separation.

Bill G

[andy.engelkemier]

I would prefer the first available colors to be red, blue, green. Then Cyan, Magenta, Yellow. Then from there, divide by the number of remaining parts, and create colors far away from each other.

Using only RGBCMY, you can create actions in photoshop that will create your selection for you. There is no red in blue or green, so if you only use RGB, then you can simply select the red channel. If you add CMY, then you have an extra step, but it's still easy. R is R - G - B. C would be B intersect G (That's holding shift, control, And Alt) minus R. And the rest follow that same formula. You can do that all in actions for those that just wouldn't remember.

The downside to that method though, is although it gives you nice antialiased edges, it will still provide you with some limitations.
Lets say you have a perfect selection for your object and you've rendered it black, but need to change it to white, while the neighboring part is a medium green material. Now, that's not impossible. It Is quite difficult though. So you go nuts with some exposure changes, several brightness contrast adjustments, and finish it off with a curves layer. You'll have a nice bright outline of green on your object.
But WHY? Because of your antialiased selection. The pixel between two objects will be a portion of Both neighboring pixels. So since you rendered black next to green, all the pixels there will be varying percentages of dark green. If you change something drastically, like black to white, then you'll end up brightening the heck out of those green pixels. That means you'll still have to edit the selection. There are some great tricks for that, one of them being layer matting. However, the green object is only on one side. So if you just remove the fringe, you'll get a Dark halo around your object where there is no object next to it.
So you're still stuck with some manual selection adjustment.

My point is, don't worry about perfect selections. It's never Really a perfect selection.

The time the rendering your selection trick works best is when you have objects showing up in reflections and refractions. You can keep one material glass (remove any tint if there is any) and get a selection for the object behind it. Clown can never do that. You need actual refraction calculation. Or that annoying teapot you have sitting over there that's visible in your Chainmail reflection (why would you be rendering that? because it's nearly impossible to select reflections work great with my example) is purple, but it should be red. So keep that chrome on your chainmail, and render everything else as selection. You'll now be able to select the objects using the object themselves, as well as their reflections. This especially works great for things like objects behind blurred glass. You could paint that selection, but it might take a while to get quite right.

What could be an awesome feature here is to select one object and say "render selection." It would render that object as flat white, with black environment, and keep all the settings of the other materials except make all the colors jet black. They should reflect and refract, and that's it. That way you don't just select your object. You select your object, plus anywhere it's seen, in the amount that it is seen.

Another problem though, becomes, certain changes require more selection that others. Changing a color in a reflection where the reflection is less than 50% will never appear to change. I created one file that I use to adjust a bunch of colors on different pages in a brochure at once (I'm actually using AfterEffects to do that, since you can link things together there). But I had to use adjusted selections for different parts. If I want to brighten a material I don't want it to adjust the shadow as much as the rest of the material. But to change the hue/color, it needs to adjust the shadows just as much as the parts that are nice and bright.