Robots in ZBrush
Richie Mason shows how to create a ZBrush droid, using hard-surface sculpting techniques and custom brushes...
This tutorial will hopefully help you gain skills and techniques that will streamline your future projects. I will take you through the basic steps I use when creating speedy robot models: we'll start with blocking out the entire model in ZSpheres, then move on to sculpting, Panel Loops and Slice Curve. At the end of the project we'll export everything into the amazing KeyShot to achieve a more realistic render, and then finish with a few small touches in Photoshop.
In this tutorial, the most valuable thing to learn is the Slice Curve / Split Hidden / ZRemesher technique. I have ended up using it in nearly all of my personal and industry work. Once you have that mastered, you can pretty much use it on everything.
Step 01: ZSpheres
We'll start by using ZSpheres to block out the body shape. Make sure you have symmetry turned on (X-key). Sometimes it helps to have a good reference to get inspiration from while doing this stage. Once you have the body how you want it, click the A-key and scroll down to make adaptive skin. You should now have a clay base to work with.
Step 02: Clay brush
Using the Clay brush, start drawing out where you want the panels and main features to be, and then use the hPolish brush to gently smooth out the areas you built up. I would recommend downloading the free MAHcut brush, although you can also use the Dam Standard. Go round all the edges with either of those brushes. When you have done that, use Geometry > Clay Polish - but be aware that every time you use Clay Polish it makes a mask around your edges, so make sure you get rid of the mask before moving on.
Step 03: Making panel shapes
First we need to fix the topology. All you need to do for that is go to Geometry > ZRemesher, though before clicking it make sure you turn the total polycount up to 100. Now you should have a nice clean mesh to start slicing into.
First we are going to start with the head by using the Slice Curve tool (which you can access by holding Ctrl+Shift) to do curves. You have to also press Alt to make a bend. Once the lines are made, hold Ctrl+Shift and click on the head, then hit Split Hidden (located in SubTool > Split > Split Hidden). This will give you two SubTools: the body and the head.
Step 04: Panel time!
Alt-click on the head to select it in the SubTool panel. You can do this next part by painting on the head in Polypaint, then using 'Polygroup from Polypaint', but for this tutorial we are going to slice it. So again, grab the Slice Curve tool and start cutting out the shapes you want. We're going to mirror everything over, so just cut what you want it to look like on one side.
When you're happy with it, Ctrl+Shift-click on different parts of the panels and keep splitting them with Split Hidden. Then highlight the first piece and press ZRemesher to mirror that piece with the opposite side. Do this for all pieces of the head, then merge all the head pieces together. Use the Move Topology brush to slightly move out the panels so some are not touching. Then all that's left to do is use panel loops, which can be found under Geometry > Edge Loops > Panel Loops. Turn the bevel and polish down, and you should have a good paneled head ready for some detailing. Go over some parts with hPolish just to give it a more refined look.
Step 05: Body paneling
Same as the last step, start by cutting out your arms and use Ctrl+Shift-click and ZRemesher to mirror them. On the body, you will want to Ctrl+Shift-click and use 'Del hidden' to get rid of hidden parts. Do this for the shoulders, elbows, knees and hips. In this step we're going to get rid of most of the torso as well, which will be replaced in the next step.
Make sure you leave enough room to show the pipes underneath the plates. When you've got all the cuts and split them, just merge them together again. Then, using the same setting in the Panel Loops panel, hit Panel Loops, but change the elevation to -10, loops to 8-9, and thickness to about 300. You may need to subdivide to make this look right, depending on the look you want. Go to Deformation and use the polish slider and Clay Polish.
Step 06: Building the missing torso
Select a part of your model with no sub levels, and use the Insert Sphere brush. Now you should have a robot with a round torso. Grab Trim Curve and start slicing away parts like in the image shown, until you get a straight boxy shape with clean edges. Now use ZRemesher to make sure you have symmetry, basically the same as before: Slice Curve, Split Hidden, and ZRemesher. Merge the torso together, apply Panel Loops, and you should have something that looks like the torso pictured in the image.
We're going to add slightly more detail now. Duplicate your torso, then Ctrl+Shift-click on a piece and hit 'Del Hidden', then use ZRemesher and Panel Loops. Now you should have your original torso with an extra panel over it. You can keep duplicating it and use the Slice Curve tool to continue putting extra parts over the panel loops, but we aren't going to add much to this one.
Step 07: Robo eyes
The eyes can be created in lots of different ways. I usually create them in Maya or CINEMA 4D and bring them into ZBrush using the cool GoZ plugin. However, on this model, I know there will just be lights with a glass shell, so there's no need.
First, go to the eye area and use the Insert Sphere brush again. Draw out your eyes, Ctrl+Shift-click and Split Hidden to give them their own SubTool. Duplicate the eyes and make the second pair slightly bigger to form the glass shells, and then turn them off so you can return to working on the actual eyes. Grab hPolish and flatten the area of the eye where you want the lights to be. (You could also use some circle alphas to create the rims if you want.)
Step 08 Fast robot hydraulics
To create the robot's under-details we are going to use the Curve Tube brush. It's a great tool for making fast wires and hydraulics. As you can see in the image, all you do is draw out where you want the wires or pipes. Once drawn out, you can change the size of them by changing your brush size and clicking on the dotted line.
Once you make one subdivide a few times, you can duplicate it and slice lines across it. Ctrl+Shift-click on the pieces, use 'Del hidden', ZRemesher and Panel Loops, then merge down and you should have your first pipe! Unless you want some variety to your inner pipes and workings, you can just duplicate them and move them next to each other. When you have enough, just duplicate and do the same for the legs, neck, and any other gaps you have left. It's always good to keep a few bendy ones in their own SubTool for KeyShot later.
With most models you may see the knee joint, and in this one you can, so I use the Insert Cylinder option with a few subdivides on it, as it won't be seen much.
Step 09: Head vents
I feel the head's looking a bit bare, so let's add a vent up there. Alt-click your main head, duplicate it, Ctrl+Shift-click on the top of the head and use 'Del hidden'.
Grab your Slice Rect tool and draw a rectangle down the head just like in the image. Ctrl+Shift-click and delete hidden again, and use ZRemesher for symmetry. Then use Panel Loops with a good thickness.
Now we need holes in it, so we're going to Polypaint in black on the piece. Once you've painted the holes you want to make, go to Polygroups > From Polypaint. To smooth them off a bit, go to Tool > Deformation > Polish by Groups and move the slider slightly. Finally, Ctrl+Shift-click the piece, use Split Hidden and ZRemesher with the same hole pieces, and Panel Loop the main piece with a thickness of 1. Now you have a head vent!
Step 10: Fine details
For this step I'll be using a free tool download from BadKing (www.badking.com.au/site): a rivet brush. Although you don't need this step, it will add more realism. Start by looking at the panels and where they would need bolts to hold them together (or maybe you just want to put bolts everywhere).
I love the bolt brush as it saves so much time! The same brush can be used to make the lights; just make sure they're on their own SubTool before making the lights, and remember to put two bolts or screws on the eyes for the pupil lights.
Step 11: Transpose Master
Even though this robot isn't going to be posed drastically, we might as well move his head and arms so that he isn't so static. Start by going to Zplugins > Transpose Master and click on TPoseMesh.
This will put all your SubTools into one low mesh that is easy to move. Mask off the body, leaving the arm out, then use the Move tool and rotate the arm into the position you want. You can then mask off the top of the arm to the elbow and rotate the lower arm, and do the exact same for the head so you can turn it slightly.
When you have the position you're happy with, go back to Zplugins > Transpose Master and hit TPose > SubT. This may take a while, so don't panic - it will give everything its own SubTool level back, only now in their new positions.
Step 12: KeyShot
Now it's time to use my favorite software: KeyShot 5. Start by merging all the SubTools that you think will be the same color and material, then select each SubTool and hit export in the top right corner of ZBrush. Do this for all your SubTools, making sure they all go to the same folder location.
Open KeyShot, import your first SubTool. In the import options dialog box, choose 'Add to Scene' and 'Keep Original'. Do this for all the SubTools. Once they're all in KeyShot, highlight them all in the scene list and click the Position tab, then select 'Snap to ground'. Now you're ready to add KeyShot materials to your robot.
For this one I'm going to use Metal > Steel and the Axalta set. Start by adding Axalta > Gun Metal to the main parts of the model, and then choose a secondary color that you like (I'm choosing yellow). Use the Steel material for all your bolts, joints and pipes. If you have a few pipes on their own SubTool, make them a different color, like red or blue. I use KeyShot's basic glass material for the eye shell, and use Light > Emissive material for the lights.
Now all you need to do is choose a backdrop image that suits it, and then the environment, which will add awesome real lighting to your scene. Now you're ready to render, so hit the render button and set the size of the image you want to produce - KeyShot is fast, so it's a good idea to make it big. On the quality, we're just going to turn the shadow and samples up slightly and turn the ray bounces up to 20-30. Time to press render!
Step 13: Scratches
Depending on your result, you might want to add a few markings like text and dirt. We will do this in Photoshop. Bring your image into Photoshop, make a new layer, and use scratch brushes or photo textures to put them over your image. Use the eraser to make sure they stay within the model, then change the layer's blending mode to Overlay.
Make a new layer, go to Image > Apply Image, and this will put everything under that layer into one. Now go to Image > Adjustment > Curves, make a slight 'S' curve in the red, green and blue, and then go to Filter > Sharpen > Smart Sharpen. Change the opacity of that layer to about 55. All you need to do now is add any text decals you want, but remember to change the text layer to Overlay as well. Now the robot is complete.