Original subtitles

Let's take a look at vertex colors now, so i'm going to go Ctrl Space just to minimize that so

we do have this as an option here, but rather than taking advantage of the workbench engine i'm going

to switch back over to our more rendered view such as the material preview and actually let's just

delete those objects there and reselect one of the objects here to get our material back, i'm going

to switch this back to slot 1 and let's bring vertex colors into the mix, so let's go Shift A

and go to input and then find vertex color so if we come over to the properties window and come

down here to the object data properties we can find here in the vertex color section there aren't

actually any vertex color sets here by default so we'll not find them in this pull down for example

it's easy to set up though, because all we would need to do is to take the vertex color output

and plug that into our emission input. now this is where things are going to get a little bit tricky

but first i just want to highlight the fact that the advantages of this probably do outweigh the

disadvantages, so with this you really don't need the use of loads of materials or textures if we

wanted lots of different colors we're going to need different materials for every shade, however

this way we can just use the single material setup and the vertex colors we can paint individually or

set per object, the downside is that vertex painting needs a little love in Blender

simple projects it's easy if you've only got a few objects, but with hundreds as we have here

it becomes a little bit of a pain, especially if we can't really join all these objects together, maybe

they have different subdivision surface levels on them or other particular modifiers that require

them to be kept separate and currently there isn't really a way to paint on multiple objects at once

but having said that i'm hoping you'll see that this is super useful and is deserving of love

so for one object it's really easy, we could either just click the plus icon here to add a vertex

color set which thankfully makes everything white so it's immediately easy to see that we've got

something there, or if i delete that by clicking on the little minus we can also come over to change

the mode and switch it to vertex paint and now we're set to whatever color we want and then we

can just left click and drag and begin to paint, we're going to switch that back to object mode

though and delete that one more time because as mentioned that's easy enough for one object

but we've got all of these objects that we need to put color sets on, and that's not very

convenient, luckily it's not that difficult but we are going to need to just switch this to a

python console for a moment but don't worry, we're going to make this very fast, i'm going to try and

explain this in a way which might help you apply this kind of method to other things, where you find

you need to do a task to multiple objects and not sure where the object is within Blender to do that,

so for this we're going to start with bpy which is short for Blender python then we can press

the full stop on the qwerty keyboard once we press tab we can see a list of all the other things that

can now follow this this is like digging down into the folders of Blender python so Blender python is

the very very root of everything, let's take a look at context, so i'll just start typing context and

press tab to finish that for me and then press the period again and then tab again and i'm going to

scroll the middle mouse wheel to see all of these options and notice there's this option selected

objects so i'm just going to come down to here and start typing selected and then press Tab and

it completes it for us and then objects and then Tab again and then if i press Enter at this point

we can see it gives us the output cylinder.004 which is the very object that we have selected

now what's cool about Python is that we can do a for loop we can tell Blender to do the same action

to a load of objects that we have selected at the same time and we know how to get those selected

objects with this line of code, but what is it that we need to do to each object, if i press the up

arrow we get the last command and the selected objects if we remember earlier when we were

talking about materials in the solidify modifier in code we count from zero, so the first object

is going to be zero, so if we do it like this within square brackets we're going to get the same

information basically and now we can do something to this, so i'm gonna press the full stop and

press the Tab key again and then what we're doing now is digging down into the options on this one

object, now i'm not gonna bore you with all those options there because i know the one that we need

is actually data from there, another full stop and press Tab again and we can see we actually

get vertex colors right here, so i'm going to start typing vertex and then Tab and then vertex colors

and then if we press Enter we're getting nothing, if we try and see if we've got anything if we

give that a zero, we see we're getting a problem because we don't have any, if i go up a couple of

times and go to the full stop again and press tab we can see we get all these options and there's

actually this option for new, if i go like this and just open the brackets, hit tab again we can

actually just go new and then close the brackets and it'll fill all this in for us automatically

so i'm just going to do that and press enter and there we go, it's done, it's created this

vertex color set for us with this line of code, i'm going to delete that again though by hitting the

minus key there, let's just select these two for example, just to do a very simple test, so instead

of doing all of that i'm just going to do a for loop, so i'm going to go for now we can

put in a placeholder bit of text it can be any gibberish really but in fact let's just use that

but basically this is going to be the object um so object gib just to prove it doesn't have to be a

word that makes any particular sense so for obj gib in bpy.context.selected objects and then hit

a colon it's going to indent it automatically for us and it's going to say right for every

object in our selected objects then we want it to do something, so we're going to go obj jib

and we're going to say take the data of that object and then take a look at vertex colors

and then do new, once we do that we can hit enter a couple of times and now we can see

we have vertex colors on both of those objects, so with that done i'm going to delete both of those

select one, go Shift G select all of type, so now we have them all selected and now we're going to

use that same code so up a few times, hit enter and then let's have it add vertex color

sets to every single object and there we go! these objects down here don't have it because if i'm

not mistaken they are curves, so they're not of the same type, so we would need to color those slightly

separately, but with this now we can switch that back to a shader editor and then we can see there

it's giving us a little warning, it doesn't have mesh data for that particular curve, but if we

select this one, we should be able to just switch that to col so just change the color for this one

we can go to vertex paint and start painting as we saw before, oh, also worth noting is it's faded

out the geometry it's darkened the geometry of everything else that we don't have selected, so

we can actually change that if we want to by just enabling or disabling this fade inactive geometry

section, i'm just going to keep that enabled by default though, so we could paint here with this

or we could go to the paint menu and just set vertex colors or we can use the shortcut Shift K

with that done we can switch over to another object and switch that over to vertex paint and

set that also and switch back to object mode and continue to work through the object like that and

clearly if we had several objects that we wanted to paint a particular color all at the same time

and we were feeling brave enough then maybe just digging into that python code a little

bit more would be the way to go, now where vertex colors becomes even more handy is that we can use

additional vertex color sets to use as kind of masks to tell it say how metallic we want

things to be, certain vertices or the whole object, whether we want to use it to drive roughness or

add a little bit of ambient occlusion and keep it all within this single material, so to set a little

something up like that we could just simply go and add in a mix rgb node, drop that here i'm going to

say set this color that we already have here into the second socket and as the factor there, let's

use another vertex color set, so we don't actually have one at the moment, but if i click plus

there we can switch this over to cal.001 newly created and set that into here and then also this

indicates that on some of these objects actually we already have quite a few additional color sets

as it was, so we might want to remove them to make this a bit cleaner, but just pressing on for the

moment. what we might like to do is come over to our vertex paint selection, make sure that we're

adjusting our vertex paint by just switching this over here, just want to make sure that we're

definitely going to edit this col.001 then if i start drawing in the view we're not going

to see anything because it's all part of this right now, so i'm going to Control Shift click

on this thanks to the Node Wrangler add-on we can just see what we're doing with this one

vertex color, so with this i'm going to set this back to white by just pressing backspace and then

go to paint and then set vertex colors and then what i'm also going to do is let's take a look

at dirty vertex colors, which is just another way of saying ambient occlusion essentially

so with that, we have some options that we can set, but i'm perfectly happy with that result and

that is now being fed into the factor, so wherever it's a bit darker ignoring the outlines of course

it will tell it to use whatever's in our second socket, which is this RGB hue that we have here

so let's Control Shift click on the mix shader and it's not immediately obvious if i just darken

that off a little bit more, we can see that coming through and if we wanted to adjust of course we

can add in a color ramp and just use this to tweak our falloff and as mentioned before we could keep

on layering these vertex color sets, so we could click on the plus to add yet another one and then

double click within the name field here to rename this to something, let's just call it metallic

for example we could use another color set to drive the metallic value, so if we were using

a Principled shader of course and if we duplicate one of these color set nodes, just bring this up

into view and then let's drag our color output into the metallic socket and switch that to the

metallic set and also just remember to use the little camera icon make sure that this metallic

here. is enabled and then with that done i can tab into edit mode for example, press Z to toggle into

wireframe and then yeah with say this selection we can tab back into vertex paint mode and then

enable our face mask here and then we can see what faces we have selected and then with this black

color here if we go paint and set vertex colors and then go back with Z to material preview

and Ctrl Shift click on this to see what we've got we can see we've now painted that whole area black

which is to say if we Control Shift click the principled psdf, let's change this into object

mode and just make this as clear as we can we can hopefully see that this area up here, actually

let's make this super shiny, so that really comes through, we can see this area up here is metallic

and this area down here is not, now as we just changed the roughness there we could

of course create another vertex color set which controlled that and so on and so on, so as long as

all the objects in the scene had those various color sets, it means that we can just maintain

this one material and get loads of different results from it just using vertex colors