Use Clip-Geo to Create a Cross-Section Toon Effect in Arnold + Free Model
Create an isometric cutaway effect in Arnold for Cinema 4D with this clip-geo toon tutorial. Download the free engine model and follow along.
In this C4DtoA tutorial, Chad Ashley will show you how to give a Bugatti engine a toon look, and then use clip-geo to create a cutaway effect to see inside the engine body.
The versatility of the Arnold toon system combined with tools like Clip Geo gives you some really interesting effects. It’s not hard to get a super realistic sketchy vibe going if you break it down into some fundamentals.
In this tutorial you’re gonna learn how to set up an isometric shot, make an interesting sketchy toon shader, and use clip geo to create an interesting illustrative cutaway look.
Download Free Bugatti Engine Model
This asset was provided by GrabCad. You can click the button below to visit their site and grab the model file.
Tutorials – Make a Cross-Section Toon Effect in Arnold
Now that you’ve got your model, let’s just in to the tutorial.
Learn More about Arnold
Ready to take a deeper dive into Arnold? In addition to all the popular Arnold tutorials already available on our site, you can now find the in-depth Introduction to Arnold training series in Greyscalegorilla Plus.
This two part series will not only get you up to speed using Arnold in Cinema 4D, you will also learn about the latest new features in Arnold GPU.
Arnold Tutorial Transcript:
Chad Ashley: 00:00 In this video, we’re going to create a cool cutaway to an effect and Arnold for Cinema 4D. Let’s get started.
Chad Ashley: 00:10 Hey, what’s up? It’s Chad here from Greyscalegorilla and in today’s video we’re going to be using Arnold for Cinema 4D to create a cool isometric toon effect using clip geo. The model I’m using is a free model from GrabCAD. I’m going to put a link to that below the description. If you want to learn all about Arnold, I recommend checking out our intro to Arnold series over on Greyscalegorilla Plus we’ve got over 10 hours of professional Arnold training to get you up and running. All right, enough talk. Let’s jump into the video.
Chad Ashley: 00:35 Okay, so here we are in Cinema 4D R21 we’ve got our Bugatti engine, which you can grab for free on. GrabCAD through a link to that down below. Let’s set up our isometric camera first and then there’ll be that first step. So let’s grab our menu, our Arnold menu over here.
Chad Ashley: 00:50 Go to Arnold camera, grab an ortho camera, and let’s zero this out and boom, zero it all out. Let’s grab a skylight and let’s turn off the render or sorry, in the viewport. So I don’t blind myself. Let’s, uh, hit go on the IPR. And there we have it. Let’s look through our ortho camera and let’s set up the, the correct isometric, uh, angles on this camera, which is going to be a 45 degrees in the heading and negative 30 and K. cool. So it looks pretty good, but we need to move that camera out of the center. And if we do that right here and we move it up, you’re going to see that we are no longer clipping, but we’re not really getting any closer to our engine. So what do we need to do here? Plus our viewport is not matching what we’re looking at here in the IPR.
Chad Ashley: 01:42 So let’s fix that. Let’s grab our camera, go over to the object and we’re going to choose projection mode of parallel. And what that does is it now aligns it in a way that makes sense for our, uh, matches our IPR. The other thing that we’re going to do, uh, you can do this a couple different ways. You can grab the handles right here on your camera and adjust the zoom. Or you can just do that right here in the zoom tab under the camera object. I kind of prefer to do it with these handles cause it’s a little bit easier to see. And then I’m going to come over to my top view. Let’s go over here and maybe now we’re just going to center this out a little bit and try to find our center and something like in this range. Looks pretty good.
Chad Ashley: 02:25 And let’s look at the all right. Yeah, that looks pretty good. All right, so we got our, our a isometric camera going here, ready to move on to the next step, which is going to be getting the clip geo working with our engine. Okay. So let’s do some clipping with our clip geo. Uh, firstly I am going to add a ground, so I’m going add a disc and we’re going to bring that size pretty high up here. I’m not really gonna pay too much attention to the lighting or anything. I’m just using a skylight in here right now just to get us started. Um, let’s go ahead and add a object that we’re going to use to clip out. We’re going to use a cue because that’s going to be super simple and I’m just gonna bring it over. Whoops. Let’s go ahead and grab a cube.
Chad Ashley: 03:08 Put it right here on the edge of our engine. That’s looking pretty good. Okay, so, um, the way clip geo works is, uh, it’s a shader, it’s a material, a, you come down here and grab a Arnold surface clip geo and whatever you assign this to, it’s going to chop out of everything in the scene. So if I put this on this cube, we’re instantly going to see this cool cross section of this engine and I can move this around and it’s super fast because this isn’t doing a real bullion. It’s doing like a render time bullion and it’s super useful. You know, you can use any shapes, you can use a sphere, we can describe a sphere, drop that in, hide the cube, throw the clip geo on the sphere and boom, there we go. We’re got like a cool like cross-section sphere happening maybe just on this edge here.
Chad Ashley: 03:57 We want to see the insides of this engine, see how it works, all that kind of crazy stuff. Pretty cool. Now if I have this go down to the ground, you’re going to notice that we’re also chopping it out of the ground too and that’s not anything that we want so we can control what it’s chopping out and what what it’s not chopping out and I’m going to show you how to do that really quickly here. Let’s say that we have this cube that we’re going to use to chop out this engine and we are going to, we’re going to make it kind of tall and it’s chopping out our ground and that’s not something that we want. Well, we’re going to control that with trace sets in Arnold here. So grabbing the clip geo material. You’re going to see here what we have a couple of different controls.
Chad Ashley: 04:34 What we are going to be messing with is tray set. We’re going to give it a name. We’re just going to say engine going to type engine in here. It could be any word you want, anywhere that you can remember. I’m just going to copy it so that I don’t have to remember to type it. So, um, right now we need to tell it. Okay. This trace set, that click Joe is working with is called engine. So anything with that tray set is going to get this chopped out. It’s going to be applied to it. So if we grab our engine and we put on an Arnold tag, we can now come over to the uh, show custom parameters. We’re gonna make sure that’s turned on and we’re using a poly mesh as our type and jump back over to the main tab and we’re just going to click one on an old tray set here to add a tray set and we’re going to type in, or I remember to copy it so I can paste it engine.
Chad Ashley: 05:17 There we go. Now we don’t have this, uh, this clip geo object chopping out of the ground. It’s only going to chop out of things that have that tray set of engine. So that is pretty nifty. Of course you can use multiple hook geo objects. In fact, you can do all sorts of crazy stuff with a clip geo and I can do some weird stuff like that. We’ll get into that weirder stuff a little bit later. But I wanted to show you the tray sets and how to initially set up the clip geo object. Uh, another interesting bit, um, that you can do as well as you can have a completely different shader inside of your clip geo object. So I have my clip geo object here. I could actually just drop in a new standard material and let’s just change the color to something that we’ll recognize and we’ll dump this into the clip geo intersection.
Chad Ashley: 06:05 And what that does is it’s going to create a completely different material on the intersecting edges. Now keep in mind the, the UV being of anything that’s intersecting is going to be taking the UVS from your cutting object. So in our case right now, this cube, so if we had, let’s say a checker pattern, oops, not a cache, but a checker checkerboard. If this was a checkerboard being fed into the base color of our object and maybe we want to like increase this frequency by quite a bit so we can see it. You’re going to notice that we’re getting the UVS from our cube. It’s not actually coming from the engine itself. So that’s kind of a, a something to remember. It’s a cool feature actually so that you can sort of have, you don’t have to worry about those edges, not, not mapping correctly.
Chad Ashley: 06:54 All right, so, um, we’ve set up our, our clip geo. There’s really not much else to it. Of course you can have multiples, you can use whatever shape you want. And with tray sets you can control who and what is affecting which, which clip geo object. All right, so we got this in a pretty good place. So I’m going to go ahead and clean this up and then we’re going to start to apply all of our cool Toon shading stuff. Okay. So the first thing I want to do is set up my scene for toon rendering here in Arnold. Uh, you can see I’ve got my a scene backup here. I’ve got a cube as my clip geo object. Uh, I don’t like the way it looks in the scene here, so I’m going to go ahead and add a display tag to that. That’s going to go into a rendering display.
Chad Ashley: 07:32 I’m going to just change this to a line mode just so I don’t have to look at that in my port and I can see my engine. Okay. Uh, the next thing I want to do is delete this light cause we are going to set up some actual like distant lights and whatnot. Next thing I’m going to do is go into my render settings under the main tab and Arnold, I’m going to tweak some things. I don’t, I’m not going to be using any volume in direct. I’m not going to use any subsurface or transmission and I’m just going to knock down the remaining settings pretty low. Actually. I think I want to leave camera AA at like four. The next thing you need to do when you’re doing toon rendering in Arnold is set your default filter type from gazillion to contour. And that’s gonna allow us to draw lines.
Chad Ashley: 08:14 We don’t have any transmission. A diffuse at Juan is fine, spec at one is fine. And then under my system I’m going to change, uh, my display bucket corners and make sure that’s enabled. I’m gonna change my bucket size to 32, which is going to be a little smaller than default. And I usually work with the initial sample level of like negative one or something in that range. Okay. So when our settings are pretty decent for right now, uh, I’ve got my setup, let’s go ahead and add some lights. I’m going to add a, uh, distant light. And immediately when I add a distant light, I’m also going to add a null. And the reason I’m gonna do that is cause I’m going to throw this null into the lookout, uh, input here on my distant light so that I can pull my distant light out and have it sort of be pointing at the center.
Chad Ashley: 09:02 And I’m just going to find a nice like lighting scenario that works for what I’m doing. A nice light here. Maybe another like key light somewhere in this vicinity, maybe down a little bit lower. And what I’m doing, I’m not worried about these shadows right now. I’m just worried about how it’s falling off on our object. And I’m going to move these in a second. I just wanted to establish a few lights in here. Okay. Um, that’s pretty good for right now. I’ll know what I need to do in far as, as far as like tweaking that in a second. Uh, let me bring also my size up to a hundred and I’m just going to region over the engine itself here. Okay. Now let’s add a Toon shader to our engine and start to work some of these, uh, settings in. Let’s go to create Arnold surface toon.
Chad Ashley: 09:51 I’m going to rename this engine and we’re going to drag this onto the engine null and immediately we start to get the toon lines, which is what we want, but we’re also getting some, some black in here and we’re going to fix that in a minute. But for right now, I’m going to actually turn off my clip geo object just so we can concentrate on the lines and where the shadows are falling on our engine here. All right. Um, so if you haven’t played around with the toon system in Arnold, it’s fantastic. I’m not going to go into detail on all the settings, but I’m just gonna kinda quickly go through how I like to set up this type of scene. I like to work with a base color all the way at one, and then I’m just going to do some simple tone mapping. So let’s grab the ramp and the tone mapping is what’s going to give us those Toon shading lines.
Chad Ashley: 10:39 So the ramp, you’re going to want to set this to you, the type to you. And then I usually just right click this and say interpal tribulation of all nuts set to step. Then I drag this around a little bit. Two levels is fine for right now. Uh, and then we just drag this and we put this into our base tone map. And wallah we have some Toon shading going on. All right, so the shadow areas are going to fall on the far left of this ramp and the highlights are going to fall probably somewhere in the middle. So let’s go ahead and make some shading levels. All right, let’s start with our base shadow and you can see I’ve got a couple of swatch libraries here, uh, that I’ve been using for this sort of illustrative marker drawing kind of toon system look. And the first one is the darkest one, and that’s going to be for my toon line, so I’m not gonna use that, but I’m going to use this one for my absolute darkest point.
Chad Ashley: 11:30 And then this knot is going to be this gray. And then I’m going to add another knot and there’ll be the highlight. All right, so now I’m just going to work in this mid. I want the majority of the engine to be this like gray color and not the highlight color. So I’m going to try to find a good spot for that. And if you notice here, if I drag the shadow out, all the dark areas become extremely as they start to take over the engine a little bit. So I don’t want that. I want to see them, but I don’t want it to be overpowering right now. And of course we can change this later and you don’t have to work with a hard line. You could work with a smooth line and you can sort of dial in exactly how you want those to be interpreted.
Chad Ashley: 12:14 Maybe you want that to be kind of a soft line. So now we’re getting some of that’s offline, but keep in mind this is a distant light and that’s why the shadows are going to be sharp like that. And of course you could change that as well. But I’m going to go undo all this stuff and get back to where I was cause I’m kinda digging that. All right. So the next thing we want to do is mess around with the toon line itself. And let’s jump back into our settings here. So if you jump back into your settings, under the Arnold main tab, you’re going to notice down here the default filter type, we changed that to contour, but next to that, or under it, it says default filter with two. And that’s going to be the, the max width of our, of our toon line.
Chad Ashley: 12:50 And that’s going to be a resolution sort of dependent. So the larger your render, the uh, the larger your line will get. So you’ll have to sort of like push and pull that around. Uh, I know that I’m working at 100% here, so that’s what I want to see. So I’m going to change this to make it a little bit wider so that I have some give and take on my toon line, uh, inside of my material cause you’re gonna adjust the, uh, the, the width of all the different types of toon lines. So I’m not doing anything too crazy here. I’m going to grab my main, uh, contour ER, sorry, my main color here, under edge, and we’re going to give it that color that I chose or I called out earlier for our two lines. Okay, that’s good. And the main edge, I can adjust the width here and I’m going to do that.
Chad Ashley: 13:35 I’m going to do that actually with a noise in a second. So I’m just going to leave this at one for right now. We could also turn on silhouette, but in an object like this that has so many different pieces, silhouette isn’t really gonna help us. So if we made this the silhouette line red, you can see like pretty much everything has a silhouette and maybe we will use that, but I don’t think I’m going to use it right now for this sort of simple setup. Okay. Um, immediately I can see I’m not getting tuned lines on a lot of these different edges that I want. So I’m going to bring my angle threshold down to maybe like 20, something like that. And you can see everything is way too thick right now. And we’re going to adjust that very, very quickly. I’m going to grab a noise and I could use a C4D noise, but, uh, I’m gonna just gonna use a regular Arnold noise.
Chad Ashley: 14:22 I’m going to look at the, uh, put that out to the beauty here and change the scale to like, I dunno, 30, something like that. Go back into the main tab. Uh, adjust the actives to maybe like five. And the distortion kind of distorted a little bit. Now I feel like they’re too small. So let’s go back to 20, something like that. So I’m just going to break up the uh, the Toon shading or the tune line scale. So from here I’m going to pipe this into a range inter, dump this into the input and then our range, I’m going to set to like 0.7 and maybe 0.3. So at the most small, the line we’ll get will be a 0.3 in the largest it’ll get will be a 0.7. Let’s drag this into the tune edge with scale and let’s look at the output of that.
Chad Ashley: 15:14 And immediately it looks more illustrative and it’s looking pretty good. I feel like it could be a little bit thicker. Let’s see what it looks like when we add a silhouette. So I’m going to pull this off and we’re going to split this off into another range and this range is going to be a little bit bigger. It’s going to go all the way to one and then maybe like an owl putting in of there. And I’m just going to pipe this into the silhouette, a silhouette with scale and let’s turn that on and let’s see what that’s doing. The red will help me understand what’s going on here, but we don’t want that for final. So let’s go ahead and see what it looks like with our main tune line. Actually, Lao is pretty good. I’m not gonna lie. I kinda dig it. And now I’m going to just dial in, uh, this highlight cause I feel like it’s a bit, it’s like everywhere right now and I don’t want that.
Chad Ashley: 16:12 I kind of want the highlight to be a little bit more just in the highlights there. All right. That’s looking pretty good. I’m not gonna worry about the ground just yet. We’ll probably do that last, but I’m going to add a little bit of speckled leanness to this. I really like the way that, uh, that looks. So let’s grab a, I could do that right in here and, but I’m not going to, cause we’re going to reference that into a couple different places. So I’m just going to grab a standard surface, delete it, grab a noise. This time I will use the [inaudible] noise and we’re going to use the boo-yah. I’m not sure if I’m saying that right, but I like to say it that way cause it sounds funny. All right, we’re going to use boo-yah and we’re going to like clamp this way the heck down and bring the scale down as well.
Chad Ashley: 16:58 And let’s see what that looks like and let’s go ahead and invert it so that we can use it as a mask compliment, boom. And it’s already connected there. Cool. All right, so let’s jump back into our engine and let’s just drag. Let’s rename this noise and let’s drag this, uh, noise into our engine as a reference and now we can sort of figure out what we want this to be. Uh, let’s throw this into a, um, let’s do a mix. And the way I’m going to do this is I’m going to mix this into the base color. Uh, so let’s do a mix here and we’re going to throw this into our base color and we’re going to make sure that we grab that color. That is our lightest color, oops, a darkest color rather. And then for the second color of our mix, we will grab the lightest color.
Chad Ashley: 17:59 There we go. And now I’m just going to tweak this noise, uh, into a place where I like it. Uh, jumping back into the noise, let’s maybe bring the scale down a little bit more and I feel like there’s probably a bit too much grunge right now, so I’m going to go ahead and clamp it back the other way. Yeah, that’s looking pretty good. Of course, I would output this and filter it in like in comp and make it look a little bit more, uh, you know, maybe a little more grain, little more tooth to it, but yeah, that’s looking pretty good. All right. Uh, I might want to add that same, uh, I need to now work on my, my ground a little bit. So let’s do that really quickly here. Let’s grab a, another Arnold tune and we’ll rename this background and we’ll drop this onto our disc and did that work?
Chad Ashley: 18:55 Yes. Okay. All right. So for this guy, I’m going to, uh, pull in the exact same line, or sorry, the exact same shading. So I’m going to grab this ramp and say copy and I could make a reference for that too, but I’m not going to cause I’m lazy. I dropped this right into our base color or boast tone map rather. All right. So there we go. Let’s make sure the base color is all the way to one. Good. All right, so now we’ve got something that’s working. And for this, if you notice, if I start to like push in the, uh, the tone mapping, uh, the knots on the, on the ramp that’s feeding in the tongue map, you’ll see the background, the shadows start to go away, which is actually good cause I didn’t want this shadow over here as sort of, uh, annoying.
Chad Ashley: 19:43 I didn’t really like the way that looks. And I’m going to just pop out to like an 80% so we can see the whole frame now. All right, that looks pretty good. Um, but I think I want to change my base color to match this color here. So I’m describing that base color and I don’t know, I kinda liked it before the way it was. I’m gonna bring that back to like a brighter color. Okay, cool. I do not want my shadow to be such a harsh edge going all the way to the back so I could get fancy and I could throw some ramps and masks and all that sort of thing, but I don’t want to be fancy. I’m actually going to just throw in a point light and drag that off over here and we’re going to raise it up into the air.
Chad Ashley: 20:29 And what this is going to do is you’re going to see, it’s like no longer a shadow. It’s actually a light. Uh, and we’re getting a harsh line here and that’s because in our background, we’re using a harsh line in our tone map. So if I right click here and we say interpolation smooth, I’m just going to start to pull these off until I fade that shadow off. Yeah, that’s looking pretty dang good. Okay, so now I might want to add some of that noise to that background as well. So let’s do that. Let’s pull our noise as a reference in and let’s figure out how we want to mask this into our base color. So let’s grab a mix and it could use a layer, but I use a mix just because it’s simpler. Um, I’m gonna throw, let’s see, what do I want to do here?
Chad Ashley: 21:16 One a mask that in via a ramp. All right, so Garver ramp here. Make sure that ramp is set to circular. Let’s go ahead and look at, connect the output here so I can see exactly what’s going on. And throw this back in here cause I just want that dirt to sort of exist under the engine. All right, so that’s looking good. Let’s throw this into a, uh, input. Let’s see, what do I want to do here? I want to use it as a mix. So let’s go ahead and do this. Let be input one. Okay. And this guy wants to be white. Can see I’ve got it flipped right now. So I’m just going to come over here and say invert gradient. Uh, unfortunately there’s no invert colors, which would be fantastic, but lo and behold, here we are. We don’t have that. All right. That’s looking good. Um, pretty good. Anyway, just a little bit of that tooth there. Okay, now we need to throw that onto our, uh, into our base color.
Chad Ashley: 22:27 And there we have it. Now, I probably didn’t, I probably could have built this in a way that would give me more control. Uh, but I feel like this is all right. Let’s bring the SAC back to a hundred and notice that the, uh, that the noise itself is a little bit tiny, which I’m not really vibing. So I might actually go ahead and jump into this noise, grab these two nodes, copy them, and delete this, this nose noise here that’s referenced and I’m copying in a completely new C4D noise just so I can adjust the, uh, the scale and let’s bring that scale up to like 40. There we go. I don’t, otherwise I don’t really see it. I don’t really feel it in there.
Chad Ashley: 23:18 Cool. I do think that our background is probably a bit too, too bright. So I’m going to just knock this down a little bit. There we go. And I might want a little bit more dirt in our, in our, uh, grunge there. So I’m gonna just pull this down. Try to get more grunge in there. Okay, cool. Jumping up back into my engine. Uh, making sure that everything is set up properly here. Let’s jump check our base color. Yep. Basis. Good base color is going to be here, so yeah. All right, that’s good. I’m going to actually bring that base color up a little bit. Something more like that. Okay. All right, now we’re getting somewhere. Let’s go ahead and initialize our cutting a cube that has the clip geo on it. And let’s address what we’ve got going on in here. Uh, okay. First thing I need to do is make sure that this cube is not casting shadows.
Chad Ashley: 24:25 Uh, so let’s go ahead and added C4D to a tag on there. Shadows, self shadow. Okay. That helps down in this area. So that’s looking good. Now, uh, and I might want to control the inside with a completely different tune. Shader. Uh, the other thing to note is now we’ve got some artifacting happening here off in the side and I’m just going to get rid of that by extending the size of this cutting object. All right, that’s looking pretty good. Okay, so let’s jump into our clip geo and think about what we want to do here. We could completely build a new Toon shader that would exist on the inside here, uh, which could work. We could do a new tune shader and pop that in and toss that into our intersection. And we could even change the line color to something like red.
Chad Ashley: 25:20 And that’s kind of interesting, but it’s not really what I want. Um, but I might want to change, uh, the, the thickness of that line or maybe the how it’s, you know, the sh the angle threshold and where it decides to draw tune line. But I’m not gonna do that because this tutorial’s already going kind of long and probably want to wrap it up here in a minute. Okay. So that’s looking pretty good. Now let’s grab our cube and let’s find like a cool spot to uh, let it go there. And maybe we don’t, maybe we want to even thicken up the line overall a little bit more. Actually now that’s looking pretty good. Uh, I do want to experiment maybe with rotating the engine 180 degrees. So I’m just going to rotate and you could see the cutting object still works, which is great. It’s looks so cool. Oh wow. That looks actually pretty sweet. Did I get that right? Let me check. Yup. Wow. Dang. Okay, so let me just take this cube now I’m going to play with it a little bit and try to find a cool spot.
Chad Ashley: 26:27 Maybe we even make it like super skinny and like put it right in the middle. Oh man, that looks cool. Those pipes on them on the back look so cool. Yeah, you can just instantly create like some crazy details with the clip geo effect, especially with Toon shading. Let’s maybe take it like right here and then you could have it like, you know, reveal back or maybe you just want to like show off like a small piece. Like maybe you’re just wanting to show like a cross section of like what’s happening inside of these tubes or something. And you could kind of like, like bring that back and like reveal some cool stuff.
Chad Ashley: 27:15 Okay, cool. So, um, I did promise that I was going to show, uh, off, like what happens, the cool effects that happen when you have multiple cutting objects. And I’m going to go ahead and save before I do that because I don’t know, this might might all just fall apart. So I’m just going to save this as a and okay. So there we go. So I’m just gonna hold down control and drag and just kind of create some copies of this cut, cut geo and instantly it kinda creates this really cool echo looking effect and I’m just gonna try to find a spot. Yeah, that looks pretty sweet. Maybe this one is going to be super thin, really long, so you can kind of create really interesting echo effects by, by a sort of breaking the clip geo effect a little bit by having it overlap, which is kind of fun.
Chad Ashley: 28:17 Um, that about wraps up what I wanted to show in this tutorial. Hopefully, uh, you got a few nuggets out of it that were useful to you. Uh, if you’ve got any questions, hit me up in the comments or check us out over on the GSG connect Slack. Uh, I’m always hanging out in there, so if you have any questions, hit me up there. Hope you enjoyed the video and I will see you in the next one.
Chad Ashley: 28:37 Hey, welcome back. Thanks for watching. Remember to check out Greyscalegorilla Plus four tons more Arnold content. If you’re new to this channel, please consider subscribing. And if you’d like what we’re doing, give us a thumbs up, drop a comment below. Hit me with a question. All right, until next time I’ll see you around. What do you think? Good tutorial. Good video, huh? Giving me the side eye.