Multiple Projections

hello everybody so one of my current students had a question about multiple projections how can you set up multiple projections inside of nuke and maybe gives a little bit of context like where would that actually be useful and why would you want to use that so just as a really simple example here if I were to come in and drop down a card and then I'll just lay this card flat on the ground and I'll scale it up and let's say I want to project an image from here and so if I come over here I'm just going to go to the drop down menu will say create camera that will create a camera for my current position and I'll make a project 3d and I'll hook that in over here I'll cook in a checkerboard over here like that and then I'll project that image onto my checkerboard all right that checkerboard onto my geometry and so when I look I can see this is what I have so now I'm going to create another camera angle and I'm just gonna go over here create another camera and I've just how about I actually accidentally went back into that camera so I just come over here and make sure I say create camera so that creates another camera over here and in this part I'll put down a color wheel and then I'll make a project 3d and so now what I can do is I can hook this camera over here put that in over here and now if I were to take this now I could project that image onto the onto the card so what I have over here is one piece of geometry and if I want to have two images on it sometimes what I've seen students do is they will take a copy of that and then they'll put it over here and it'll make like a scene to merge these together so then you have that and then you have that and then after that they might make a scanline renderer and then hook it in here and then hook it into wherever you're gonna render from so make another camera to render and so if I look at it then I get something like that the problem with that though is that you're duplicating the geometry and another thing is that I wanted the color wheel on top and so I can see right now that because they're in exactly the same place there could be some confusion as to what actually goes on top of what piece of geometry so I may have to take that card and just raise it up just a little bit universe without the I know that the color wheel is supposed to go on top of it the downside is that I'm duplicating geometry and you know for curds it's not such a big deal but it adds more overhead into your scene and if you're using assets from the 3d Department it could be that these are a little bit heavy and you don't want to duplicate geometry inside of nuke if you don't have to because nukes 3d system is kind of old and it you know it slows down if you have a lot of geometry in it what's worse is sometimes I see okay we'll don't do it that way then they might make another scanline renderer over here and so then they don't have them kind of merged together and so and then they have one scanline renderer over here and then they have this one over here and then they would make an emergency it is the background and this is the foreground so I've seen this from other people as well and this is bad because you want to minimize the amount of scanline renderer nodes that you have inside your scene you know you can't you can have a scene that has multiple scanline render nodes if you need them but you want to have as few as possible you don't want to have any that are unnecessarily because again it slows down your scene considerably just by having a lot of them especially if once you start increasing the multi samples in order to get some motion blur happening or to increase the quality then you know it'll begin to slow down your scene so we can actually get rid of these notes over here we don't actually need those and what you can do instead is there's a node called merge material or merge mat and the project 3d node is technically a material node so if I drop that in over here and then plug that in over here then I get basically the same thing that I just had what's happening is that in the 3d space I'm merging these two materials together and then they're being projected onto the geometry it's also kind of cool is inside this merge material right now it's set to over so it works just like a merge nodes over but there are a few other modes that you could use in order to blend things together it doesn't have as many options as you know say Photoshop or the merge node does but you can have things kind of poke in and out of alpha channels or cut alpha channels or you know limit the visibility based on the other layers alpha Channel so it does have some flexibility there and this is also merge lets do if you have any extra channels like if you had if this was like a 3d render and you had your other render power your other render passes inside here you just say merge all the other channels along with the RGB okay so this is the the theory behind it of how you could set up multiple projections and I'm going to pause the recording here and just set up maybe a couple of really simple shots where this technique might be of interest where you may want to play around with it a bit all right so maybe we have to do some projection thing on the tabletop over here so I have a piece of geometry that I made from the point cloud generator so I just made this piece of geometry over here and so maybe we need to project on that so what I could do is you know in my 3d scene over here I could pick a frame and so maybe I want to have one frame that's back here that gets you know maybe like some of this information but then we eventually do get really close so I need to have some of it at high resolution so maybe I want to get like I want to use the last frame because that's been were really close but then I pull back a little bit and then I'm gonna get like this part over here but that's at frame 102 so I want to get both of those bits of information on my projection so what I could do is if I go over here to frame 167 and if I make a frame hold and so that's going to freeze my camera at 167 and then I'll just hit alt F or alt K sorry to make a clone and then I'll clone that with a piece of footage that I want to project and then I'll use a project 3d and then I'll hook that into the camera I'll hook that into the footage and then hook that into the mesh so when I look I have this but you can see you know this is great for if I plug that in and I look through the camera I can see over here that you know this is gonna be very high-resolution because you know we're taking the last frame just before we reach the edge of the frame but then as soon as I pull back I can see that I don't have this over here so if I want to get this patch but I still want to keep the high-res stuff that I had before then I could just set up another projection so maybe I'll come over here and I'll make another frame hold and then they're all frame hold it at frame 120 I'll hit alt okay and then I'll hook that into the camera I'll do a project 3d hook that into the camera hook that into the image and then over here now if I were to just take the whole thing and place it over here then I can see that now I would get everything that I made my geometry kind of get up to but over here you can see that that's gonna be a little bit soft because we're a bit further away there might be some motion blur on it let me just make sure I got enough oh maybe I'll go back a bit further maybe frame 102 so I'll say 102 that'll change both of them because they're clones and then now when I look at it over here okay so I have this I need a bit more geometry to get the full length of it but for now just pretend that's there and so I can keep the full resolution if I do a merge material and so I could say that this is going to be the lower layer and then this high resolution is gonna be the upper layer and then I can just click that in to my geometry so now you can see the difference you see how that over here is a lot sharper than the layer now you'll see a bit of a line there but then you just add some feathering you could roto that out so on the top layer if I had this over here and I just want I don't want there to be a hard line there then I could just make maybe like a roto and then maybe just wrote out the area that I want to keep oops so I'll just go over here and just say keep this and then maybe feather that so then it transitions to the lower resolution one maybe something like that and then I can do a pre molt so when I look at it it's going to give me that transition and then when I look over here I'll have that transition over there and maybe I'll just set this to auto alpha so that that has an automatic alpha Channel and over here I'll set this one to replace the Alpha Channel just so that this lower layer level this lower one will have a solid white alpha on it so it's just all I'm doing is over here that's just giving it a white alpha and then over here that I want to replace the Alpha with this one so over here I just hit replace so instead of having a solid alpha because it's just gonna draw white on top of white so I say replace and then it replaces it and then the pre molt and then the merge material that goes onto the mesh and then I goes over here and then if I do a scanline render and then hook it in then I'll have that and so you can kind of see the transition here between the one that's a bit higher resolution and then the one over here that's a little bit noisier and a little bit softer so that's another use of where you might want to use the merge material basically any time you want to project multiple images onto one piece of geometry you could use it then now just something to watch out for is you know is when I start doing stuff in 3d it's very easy for your nuke script to get really messy and you know usually what I do is I try to I try to not do this so what I'm working I've mentioned this I think to most people that are in the course but I do like to change the node graph colors so green into the right I'm sorry down into the right and then up and to the left and if there's any dots I like them to be a little bit bigger so now I have this that helps make it a little bit more readable and then what I like to do is if there's something that's feeding into a lot of inputs I like to kind of put it up and same thing with this piece of footage I like to put it up and then they're gonna feed in and then I start making branches so I'll hold down control and then I'll start drawing out these lines here and then if this is all going across I'll try to find like the farthest one maybe that one is this one over here is like the farthest one and then I look for anything else you can kind of get a ride on that line so I'll make another dot over here and put that across so now this is going across over here look for where else who else is using that well this point cloud generator is using that so I can just make another dot and try to minimize the amount of diagonal lines that are in your file so if I come over here and then this one is being grabbed from there this one's being grabbed from there and then this one is actually coming over here so just by doing that that's already helping with the readability of this and then over here we have one projection setup over here that goes into the project 3d and so that could be placed into a backdrop so again just for readability over your scene so if I grab these and then put them into a backdrop you can move the backdrop without moving the nodes if you hold down control otherwise if you grab a backdrop the nose will be selected and then they'll move around with you but if you just need to move just the backdrop to hold down control and then you can move that around underneath and then over here same thing so now these are coming from the image so the image I could do the same thing that I did over here I usually put a dot a bit further down and then I'll have things branch out from there and in some cases when you're doing dealing with a kethry D setup that's not really built to have really smooth like it's hard to avoid diagonal lines like here there's a dead no line coming in but you do your best just to try to make it as readable as possible and so again here's another projection setup that I have over here so I could put a backdrop with that and then the point cloud generator you could either keep it or sometimes you just can put it off to the side if you don't need it anywhere so it makes it a little bit more readable than what you what I had before and one other thing that I don't know if I really touch on too much is in the in the 3d tools over here there's a shader and one of them is called film at our fill material and where this can be useful for us just to poke holes by using a piece of geometry so this isn't the prime example or like a it's not a great example but I'll just want to show you what this does basically what film at will do is it'll put in a color into a into a piece of geometry including black including and it'll do that on the RGB so if I just came in here and if I made a just a box or a cube and I'll plug that into the scene you know just make it a bit smaller and maybe I'll scale it up a little bit you know I'll just take the scale you know what Phil Matt will do is if I put that in as the material then you'll see over here is whatever color I put in that's the color it's gonna render out but what this is really useful for is it's good to poke holes in your geometry if you need to make a mat for something then this is just like a piece of geometry that's in your scene but it's just colored completely black so that if you need to rather than make like an alpha it'll just fill black in that area and because it's a 3d objects in your scene if you had a card that was in front of it or behind it it would respect that 3d geometry so sometimes that can save you like instead of row towing something sometimes you're able to do it in the 3d scene just with this fill material so sometimes that can be helpful if you have a complex scene and you need to kind of poke a hole through certain areas you can do that with this okay that's just a really quick lesson so hopefully this is helpful

Channel: Joe Raasch

Views: 3,611

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Id: W6GQ6dWpBx8

Length: 18min 16sec (1096 seconds)

Published: Thu May 09 2019