UnrealReader | Visualizing Unreal Scenes in NukeX

with the addition of unreal reader to the nuke x toolset nuke users can tap into the rendering power of unreal and streamline their workflow without ever leaving their compositing application in this short tutorial we'll have a look at the way you can use nukex to easily augment any render coming from unreal and add or alter any elements that might need additional work to capture our output from unreal to nuke we require a few prerequisites namely unreal engine running on a local or remote machine the nuke server plugin installed within unreal instructions on how to do so can be found in our documentation and access to nuke x 13.1 or higher also if you would like to follow along we will be using the subway sequencer project available for download from epic we'll start by opening the project we'd like to work on within the unreal engine once the project opens we can confirm that the bridge between nuke and unreal is up and running the order of actions here is not important what matters is that nuke and unreal can communicate with each other to do so let's go to windows and find the nuke server entry click on that and the server window will pop up start the nuke server from here and now we are ready on the unreal side we can return to our nuke session once in the nuke session the first node that we'll need to create is the unreal reader node this tool facilitates the connection to the unreal engine and it will allow us to harvest the output coming from unreal with the unreal reader in our script the connection to a locally running instance of the unreal engine will be established automatically or alternatively we can connect to a remote machine running unreal in this case unreal is already running in the background so we are good to move forward once the handshake is successful we'll see the first set of pixels appearing in nuke as a next step we need to choose a map from our currently open unreal project and a shot to work with in this case we'll select shot number 170. once we have our shot selected we can go ahead and start thinking about render passes that will be needed to successfully execute our image alteration from the list of passes available in unreal since we are replacing a part of an existing element in the shot we'll need a way to align our new nuke created objects to the objects already present in the scene to help with this we'll need the world position pass that unreal engine provides next we'll need to be able to isolate and mask the objects in the scene since the foreground characters will partially obscure our composited in element kryptomat paths coming in from unreal should cover most of our needs so let's go ahead and select that one it's worth noting that aside from kryptomat we can also use the stencil layers approach to isolate rendered elements in an unreal reader but for this example the kryptomat will be more than sufficient let's also enable the scene depth pass for post depth of field effect once we're happy with our selection we can confirm that the selected passes are being received by nuke by pressing the update channel list button and we can see them in the channel list we can optimize our workflow further by pre-rendering the images to disk to avoid unnecessary communication between nuke and unreal just remember that new passes can be added at any point if needed let's go ahead and render out our scene and once done let's enable read images directly from our unreal reader node now that we have our prep work done let's create a 3d reference representation of our scene so we can place our new element accurately let's start by shuffling out the world position and the rgb layers once done we can create the position to points node and connect our new shuffle nodes to their respective slots this combination will provide us with an accurate 3d representation of the unreal scene in nuke's 3d viewport let's go ahead and create a card that will represent our new element and align it to the reference points in the scene once done we can create a scene node followed by a scanline render node and connect them all in succession to match the motion of our new nuke generated element and the unreal scene we will also need a camera that is matching the animated shot camera from unreal luckily the unreal reader can easily generate one for us let's return to the camera tab under the unreal reader and click create a camera leaving the rest of the settings on default with the camera created let's connect the new matching camera to the cam input of the scan line render node now let's merge the output coming from the scan line render with our main stream coming from unreal and let's have a look at our progress so far as you can see first we will need to mask the rendered card with our foreground characters let's go ahead and create the kryptomat node and use the unreal stream as the input we will be presented with a visual representation of all the available elements in the kryptomat pass we can use the picker tool to select the elements we would like to generate masks for or we can use wildcards to select all the elements that share common naming patterns with our mask created we can now use it as the mask input on our merge node and then invert its effect as you can see our card appears now correctly ordered behind the foreground elements but its shape is still not matching the rounded shape of the screen we're placing it into and in this case the crypto map pass won't help us either since it doesn't contain the screen as a separate element to remedy this we can use nuke's 3d projection system to quickly make a matching roto shape and project it onto our 3d card let's start by creating a roto paint node followed by a project 3d node for the project 3d camera input we can use our unreal shotcam frozen on a frame where the element is fully exposed and clearly defined in this case let's use the first frame now let's connect the output from unreal to the background input of our roto shape to get the proportions and placement correct for our mask and let's go ahead and trace the element we would like to isolate once we're happy with the roto shape we can check to replace the channel's checkbox on our roto node to remove the background pixels we used as reference let's have a look at our result now as you can see our projected mask now works quite well to add our new element that goes into the screen let's duplicate our 3d setup bring in any footage you would like to use in the screen and replace the existing connection copy our projected mask as an alpha to the render of our new element and add a few beautification final touches with the addition of an unreal reader the unreal engine can become a powerful extension of nuke's built-in toolset there you have it we hope you enjoyed this tutorial and happy compositing

Channel: Foundry Learn

Views: 11,602

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Id: yIXjqnH8GCI

Length: 6min 40sec (400 seconds)

Published: Tue Nov 23 2021