Nuke - Básico 04 - Channels & layers - Treinamento em português

Hello, I'm Magno Borgo and this is another Nuke tutorial In this video I'll talk about management of Channels that permeate all the software functionality usually for those starting on Nuke it can be a difficult subject to understand because it works in differently from other software so what is a "channel"? in the images we have color channels which is data, that represents each color necessary to build this image so.. we have the red, green and blue channels If you look in Nuke when you pass the mouse over the image on the Viewer you have some numerical information in the lower right corner there we can see the values ​​for each pixel for each of the color channels we have: 0.41 on red, 0,41 on green and 0.28 on the blue at this pixel where the mouse is Nuke will work with 3 display channels red, green, blue, and also the alpha channel which here is the case in is zero (white) An interesting factor here is that Nuke works at 32bits and the amount of information it can store at a 32 bits channel is very big and this also means that we can store informations in there, not just color we can have other types information on channels for example, the pixel depth determined from the distance from a camera. The great thing is that Nuke can work with many channels it has 1023 available channels. What is the usefulness of these channels? You can bring more information to manipulate the images and you can also store information inside a channel at any time and elsewhere in the composition you can you use this information it is always available for you. So, I will show here one example of an image a 3D render that has multiple channels inside it. I have this car and inside this image we have multiple channels How do I know it has several channels? if you observe the node preview icon you will see that it shows the channels at the bottom left for example RGB and RGBA here in the car icon and it has this darker green icon representing non-standard channels so this green icon means that we have non "standard" channels in this picture an easy way to view channels is to use the LayerContactSheet node You can see all Layers that contain channels in an image I will maximize the Viewer pressing "space" and we see that within this image, whose format is. exr there is the beaty pass in a RGBA channel we have the Ambient Occlusion render pass we have a Diffuse channel, and so on... multiple channels within this image which is something usual in a 3D rendered image this will allow a great range of manipulation to achieve a final composition. If I have the reflection channel for example... this one here I can manipulate this reflection leave it stronger or weaker to get the result I desire in my final composition. Let's see how the channel visualization works. How this is organized here? Within the Nuke we have something that we call "Layer", sometimes called "Layer Channels" here where the mouse is. Within Nuke we have some Layer Channels: for example here we have the standard RGBA. Within a Layer Channel, you will get up to 8 channels the the most common Layer Channel is the RGBA and it has 4 channels on it: the red, green, blue, and alpha channel we have other standard channels within Nuke like the "Alpha" which has only the alpha channel and we have some other standard channels here, names that are "reserved" for internal software use So... when you start a new project, you will have these Channels. Pay attention: when you have a Layer Channel viewing the image, we can only see 3 colors on a monitor: red, green, and blue, right? at any momento you can see a single chennel color independently, pressing shortcut keys "r", "g", "b" and "a" if I press R here, I'm viewing the red channel As this letter (on the image) has only red color on it it's the only letter appearing in this channel channels are represented as grayscale whereas black represents zero and white represents the value 1 (usually). if I press "r", I go to the red channel pressing "g" I'll go to the green "B" for blue and pressssing "a" I go to the alpha channel. That looks interesting: the alpha channel when I'm on the normal view it does not appear, it is always a separate visualization and its display is always black and white. When you're inside any channel for example here I'm in the red, you press the same hotkey to return to "standard" view, So here I press "r" and go back to standard (rgb) if I'm in green, press "g" again and return to standard or u come here in this menu and click in "rbg" to return to normal. :et's talk about where the confusion begins for anyone starting in the software. I will create a Merge node By pressing "m" and you will see this type of configuration, on the node properties will be very common because at every moment you'll be manipulating Channels. This type of control here determines which Channel comes in/out, is kept/discarded, etc. When I'm with a Layer Channel RGBA, I have all 4 channels represented here on the side changing to the Layer Channel "Alpha", it has only one channel and this Channel is putting alpha in of the red Viewer color. This causes some confusion for the novice user because if I'm viewing the standard RGBA here I press "a" and see the alpha, but if go to the Layer Channel "Alpha" the alpha channel is being displayed in red color then... it is a little bit confusing what you have to understand here, is that the channel display is limited to 4 "Viewer positions": red, green, blue, and the special alpha channel. I will bring a picture that I prepared beforehand which has totally arbitrary channels. Take a look: it is an .exr: normally this filetype has several Layer Channels inside and each of these layer Channels can have multiple channels on them I know there are special channels here because the green icon in the bottom right corner of the preview of Node. How can I know what are these channels? when you import an image inside the Nuke which has non standard channels the new channels will appear automatically here. here I have a Channel called "frutas" (fruits) this is a completely arbitrary name and herein the middle menu, it is possible to see the channel names look: I have banana, cereja (cherry), maçã (apple), melancia (watermelow) and morango (strawberry) names are entirely arbitrary and often we'll have information that is completely different within each channel anyway.. I'm just trying to show that you may have anything within a channel and this information will be accessible. I want to view these channels, how do i do that? Bring the Layer Channel here, "frutas" in this case we have to connect the node to the Viewer to see it, I'm with the information there now How to know what's inside, how this works? in the red channel, I have some information I associated the images of the fruits with the name of each channel I have banana here, in the green channel have cherry and apple in the blue can be pretty confusing to view the information, mainly because they have nothing to do with the color of the channel Red has banana... so this is what causes confusion and if we look it all in RGB, they are all mixed, It does not make sense in terms of color. How do I predict how this will work? One simple way is to use a node to Merge and load the Layer Channel. when you load a Layer Channel, you see what kind of Information associated with the display color on the viewer then looking here I know that banana is red cereja (cherry) is in green, maçã (apple) is blue and melancia (watermelon) is on the alpha. Let's see: if you press "a", it's there the image of the watermelon and I know I'm in here there is another channel, the morango (strawberry) that is not showing up Why it is not showing? Because I only have 4 display "channels" if I have more than 4 channels in a Layer Channel (which can have up to 8) the only way to see the channels number 4 to 8 is putting them in for display in the alpha and it is precisely for this that we have this middle menu here This determines which channel will appears in the alpha here, when I enter on the alpha I'm seeing melancia (watermelon) because by default, when the Layer Channel was created, the melnacia was in position number 4 if you want to see any other channel in alpha just change the menu here in the middle and set iy to another channel so let's see here ... morange (strawberry) and now we see that I put the strawberry on the image How to create new channels within Nuke? There are several ways ... Let's look at some options the first is importing files with non-standard channels Layer Channels are automatically created then I have the frutas (fruit) here If bring up another image for example this car when I import the image the Layer Channels are created: I have now Ambient Occlusion, Diffuse, Incandescence... etc. this is a way A second way is to create a new Layer Channel here on the menu click "new" and there you can create a Layer Channel with any name so I'll call this one the "frutas2" (fruit2) and the channels are the names that you want you can use the preset RGBA or you can use any names that you want I'll create abacaxi (pineapple) uva (grape) pera (pear) and laranja (orange) 4 channels .... you can have 8, the minimum is 1 and the maximum is 8 I'll add one more here: maçã (apple) I now have a new Layer Channel: frutas2 and within this Layer Channel, you will see channels inside this middle menu usually the position going to the alpha is the position number 4 let's see here, if I edit it the fourth position here is laranja (orange) and all other names appear here there may be times when the list is quite large remember that to view channels at any Merge node you can load the Layer Channel and see what channel is shown in which color. Finally, a brief review: We have multiple Layer Channels in Nuke and each of these may have up to 8 channels in them and we can see only 4 by default on the middle menu we can load any channel in alpha for viewing and here we can see Viewer channels through keyboard shortcuts The representations of the channels on the Viewer: red, green and blue I hope you guys enjoyed this video and that it has been enlightening. For any questions, suggestions or requests leave a comment on the video page. A hug and until the next tutorial! Subtitles by the Amara.org community