Video Transcript
Instantly align Unreal Virtual Production sets and real studios using Aruco Markers!
Greg Corson · 12,559 views 2 Dec 2022 #unrealengine #virtualproduction #aruco · Duration 14:44 · youtu.be/J2pnk97zIDg
To do a virtual production shoot you need to align your virtual set and real studio so things on both of them will line up properly. Here's a method to instantly do this without a lot of tedious measuring and doing alignment by eye. You just put an aruco tag in your studio, put a matching one in the virtual set, two clicks and everything lines up instantly! A real time saver and it works with any tracking system. For example this can be used to make your talent appear in any specific spot in the virtual set and adjust other tracked objects and studio lights so they will appear in the right places too. It can even be used to align a greenscreen table top with a table top in a virtual set, so
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if you've been doing virtual production you know this problem you come in to do a shoot turn everything on your real Studio isn't aligned quite right with your virtual set well now there's a real quick and simple solution and I do mean quick all I have to do is put a paper or Roku tag on the floor of my studio and put a similar tag in my virtual set that I want to align with it now watch or you'll miss it one click and another and everything is now aligned here's a full screen version so you can see it better
here's another example I put the tag on a chair now one click two clicks and now the robot is standing on the chair if this sounds familiar to you you may be one of the people that saw this video on YouTube where another person shows how you can take a green table use an arucou tag and align it with a set of a bar so that the actor will appear to be leaning on the bar I'll leave a link to this video in the description below it has a lot of useful
ideas but it didn't show how to actually do it the nice thing about this method is it works with any kind of tracking system it doesn't matter what I've shown this in some of my other tutorials but I didn't spend much time on it now I'll show you how to make the aruko tag resource and how this alignment system works the first thing you need is an image of the uruko that you're going to be using for tracking and aligning I usually go to this site there'll be a link to that in the video description down below then you fill in the type of Veruca that you want I've chosen the 6x6 version marker number eight then all you have to do is save it and print it out you can do that two different ways you can open it and print it with your browser or you can save it as an SVG and then
open it and print it later I like to save it as an SVG because it makes it easier to create an image that I'll use in unreal later either way you want to print it as large as you possibly can without clipping off any parts of it bigger arruko tags will work better if you need to use them at a distance from the camera if you downloaded an SVG it'll show up on your disk looking something like this you can usually just double click this and your browser will open it again and then you can print it out any size you want you also want to convert this SVG file into a PNG or jpg image you can usually do that with a paint program things like Photoshop paint.net and a lot of other programs will open up the
SVG and let you save it again as a PNG if you don't have a paint program that can do that search for SVG to PNG on the internet and you'll find a number of different options that'll do the conversion for you online now we'll make the aruko tag resource that you use inside of your unreal projects start by going to your content folder right click and choose new folder and name it something like a roko tutorial or whatever you'd like to call it and go inside now go to wherever you save the PNG version of the uruko tag and drag it into unreal then right click on it and choose create material
now right click in the window again and choose blueprint class and select actor and I'm going to name this oruko 6x6 number eight double click it to open it and if it doesn't come up with the viewport showing click on viewport to show it and you should see something like this now we need to add several components start with a static mesh then add a plane then add a calibration point
and select that and duplicate it three more times now select the plane come over to its material and find the six by six material you just made a minute ago and now it looks like your tag just to add another reference to make it easier to align things I like to add an axis that's what this static mesh is for so select that and come over to the mesh find the axis
this is included in most unreal releases and now you've got this axis here I also find this axis easier to see if I make it a little bigger and color it so I'm going to set the scale on it to 1.5 and then I'm going to come to the material and choose a green material now we got a nice visible axis to check that everything is aligned correctly rotate your view of the tag until X is pointing up and Y is pointing to the right now if you remember the tag that you
printed out earlier the top is actually this bit here and that should align with the x-axis you can see it doesn't so we're going to give it a little spin just come over and do a z-axis rotation of 90 degrees and now everything is lined up correctly the last thing we have to do is set up these calibration Point components and for unreal to recognize them in your uruko tag properly these have to be named in a certain way the first one I'll select and I'll rename it to dict six by six 100-8-tl which stands for top left
you may remember we selected the 6x6 hypervaroco tag anaruko tag number eight if you used a different size uruko tag or a different number Tag replace those in these names here now I'll rename the rest of these this one will be renamed to BL for bottom left ER for top right and the last one BR for bottom right now select all four of these go over into the details on the side and find visualize points in editor go ahead and check that and then right below it there's a field
called Point visualization scale and I like to turn this up to about two now we just need to move these points to the right spots on the tag start with top right because it's the easiest one it's at 50 50. bottom right will be at -50 bottom left is at minus 50 minus 50. and top left is at 50 minus 50.
you can click through these to make sure that they're all in the right place top left bottom left top right bottom right now we've built us a tag and it's ready to use but it's kind of big it's actually about a meter across right now but there's a quick and easy way to make it sizable to whatever size you need and make it very easy start by creating a variable and we'll call that tag size in centimeters make sure that's a float
now go on to the top here and click on construction script the construction script is a special blueprint that runs every time an object gets created or changed so what we're going to do is make this resize our tag to the size we want it to be so drag this off and and do a set relative scale or the default scene root now we'll get our tag size variable that we just made
make a divide node and divide by 100 centimeters which is one meter then I split this scale pin and I copy that value into the X and Y scale and Z scale now it's ready to use and it looks like that the last thing you might want to do is set a default for your tag size
here I've set it to 15. or 15 centimeters also go back over to the tag size here and open the little I button that'll make sure that it's actually visible to you when you drag it out into the world now back at your unreal scene just take the uruko tag and drag it out I'm going to position it at 0 0. and I'll also rotate it 180 degrees so it's facing in the same direction as
my camera will be and is same direction as the uruko tag that I'm going to put on my floor if you've been doing virtual production and followed some of my tutorials or some of other people's you know that you need a calibrated lens file to get good results so you probably already have one of these I'll put links to My Lens calibration tutorials down in the description below if you need them part of that setup is to have a camera parent that your camera is attached underneath you also want to attach any other tracking devices underneath the camera parent so that they'll all follow along
when we align the set so now this is completely ready to use I'm going to open up My Lens file and that opens up the unreal lens calibrator I'm going to go back to my unreal screen connect that up to my camera and then go back over to the calibrator so now you can see a combination of the real world and the cg1 and like I did at the beginning of the video all you need to do to align the two go to the Noodle offset tab
choose noodle offset aruco markers use the uruko you put in the scene then click on the screen it detects the uruko you apply it to camera parent and everything jumps into alignment again and that's all there is to it everything is nicely aligned with just two clicks in this example I'm putting my robot into a video feed of my real Studio but you're probably doing the other kind of virtual production where you put a real person recorded on video into a CG Studio this works just as well for that
just throw your Roku tag down on the floor in your studio where your actor is going to be standing and then move the uruko in your Unreal Engine Studio to where you want that actor to appear do the alignment and everything will just work remember you don't have to recreate the aruko every time you can just copy it into a new project using the migrate function in unreal and you can do the same thing with your lens file so you can keep reusing them in Project after project you only have to do the hard part of making the resources once and that's all areas to it I hope you'll find this a useful tool for aligning your sets when doing virtual production if you like this tutorial please remember to like comment and subscribe
it really helps the channel out and I'll see you again next time
Transcribed 20 blocks · Source: YouTube