How to sculpt a character in VR

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You may be forgiven for thinking that the Oculus Rift VR headset was created solely for use as a gaming device. That is no longer the case, as there are now lots of creation tools springing up, including VR sculpting and painting apps.

This project will show you how virtual reality can be used in a character concept pipeline. We will explain how to sculpt in VR and how to paint a character model, in this case a robot from a mining colony. We will be using a few concept sketches and paintings that are imported as reference planes. 

The final model and scene is 'photographed' in VR with a number of different lighting scenarios. These are then taken into Photoshop for compositing into a final render.

The software we will be using is Oculus Medium, which is an immersive virtual reality experience that lets you sculpt, model, paint and create objects in a VR environment. The software enables you to create expressive works of art, whether you're a total beginner, an aspiring creative or a professional artist. Using Oculus' Touch controllers enables the user to employ intuitive hand gestures and movement for a natural, tactile experience. The final sculpt will be a character that can be posed and exported with painted colour detail, for use in another app or for 3D printing.

01. Set up Oculus Rift

Take a while to get your VR legs before jumping in

The video to accompany this tutorial (which you can download here) is recorded in VR and the experience that you will see on screen is not representative of the full experience. Once you have your Oculus Rift and sensors all set up it would be beneficial to spend some time understanding how to hold and use the controllers. Open up Oculus Medium. The first video starts as we enter the Oculus Medium scene.

02. Import reference images

Find some robot concept art to use as reference

On your computer, look for the default Medium folder and look for a folder called _Import. In there you will find a folder for images and a folder for meshes. For this tutorial we bring in some robot character concept art to use as a guide in the scene. Pull back on the Support hand thumbstick and click the reference button at the bottom of the panel, which resembles a book. This will bring up the References panel. Click Import to add any images that have been saved to the _Import folder. They are now available to use as reference.

03. Add the reference imagery to the scene

Select 'Move with sculpt' for your reference images

After selecting the images you imported, they should appear in the VR scene. Pull back on the Support hand thumbstick to exit the reference panel. To move an image, click on one and it will display a green outline to show it is selected. Pressing the green button on your Tool hand will bring up options for the reference image. Now hit the green gear button and select 'Move with sculpt'. Move the reference image to a position that works for you and enables you to model in front of it, and repeat this for each of the reference images. 

You can also delete images from the scene using this options panel. If you don't select 'Move with sculpt' the image will lock to a position in the scene. This can be useful for adding signs and graphics to your VR scene.

04. Block out the base of the robot

Enable the mirror function to save time on your sculpt

We will do a very rough layout model. Push forward on your Support hand thumbstick to bring up the tool radial menu and make sure you have the Clay tool selected. Pressing the trigger on the Tool hand adds clay to the scene. As the robot is symmetrical, we need to enable the mirror function by clicking the yellow control panel button on the Support hand and selecting Mirror.

05. Change default stamps

You can customise the brush shape to suit your needs

We started sculpting with the Clay tool and with a default sphere shape. Although this is the most basic sculpting tool in Medium, it can be customised with a variety of different brush shapes. 

To change brush shape, press the green gear button on the Tool hand controller and at the top of the panel you will find the default brush shapes. Select one to make it the active shape at the end of your sculpting tool. Medium comes with a large catalogue of stamps, which are located in the menu below the default brush shapes.

06. Split the model into parts

Split your model into layers using the Cut tool

Use the Cut tool and slice up the model, which automatically creates a new layer for each part. Push forward with the Support hand thumbstick and select the Cut tool on the radial menu. Remove the head first by moving the line through the neck while pressing the Tool hand trigger down. If you have done it correctly the head will be in a separate layer.

07. Navigate layers

Make sure you know which layer is which

Pull back the Support hand thumbstick and make sure you have the Layers panel selected, the first button on the row of icons at the bottom. From here you can rename, delete and merge your layers. 

For example you can use the eye icon next to the layer to hide individual layers as you work. If you point your Tool hand at a part and hit the trigger, you will automatically select the relevant layer, indicated by the yellow highlight. To cut a particular layer, re-select the main layer and continue cutting the model into individual parts.

08. Adjust environment settings

With the scene settings you can configure the world to your liking

So far we have been using the default environment settings. You may want to configure your environment to suit your own style. To do this, pull back on the Support hand thumbstick and click the button that resembles the world. 

From here you can change the sun colour, adjust the sun brightness, turn off the Skybox and change the background colour. You can also turn off the ground plane and just see the background colour you have chosen. Configure the world to suit your style and play around with the settings until you are happy.

09. Adjust material settings

Each model per layer can have its own material, enabling you to mix things up

Seeing as though we are making a robot, let's change the material to a metal shader. You can set a material for each model per layer so you will have to choose each layer and adjust it to suit. 

To do this make sure you are on the Layer menu again, then select the part you wish to change the material of. With the layer selected, press the green settings button on your Tool hand. On this menu, change the material by clicking Metal at the top middle. Now you can change the roughness, diffuse settings and the occlusion of the material.

10. Pick a colour

Use the colour palette to choose colours, or just grab one you've already used with the colour picker

As we are about to start working on each layer at a more accurate level, we might want to change the colour as we go along. Make sure you have the Clay tool activated and click the colour palette button on the Tool hand. Use the picker from the top to select an existing colour from your sculpt, or select black or white. Any clay you add from now will be the colour you have selected.

11. Increase layer resolution 

Make your sculpt less blocky by increasing the resolution

For some areas of the model that carry a lot of detail, you may notice that when adding clay, the resulting brush stroke is blocky and jagged. To solve this, it is worth increasing the resolution of the layer. Go to the Layer menu. On the right-hand side, you can find the Increase Res option to increase the resolution of the selected layer. 

Every time this is done, the layer bounding box gets smaller, increasing the density of the voxel grid. Doing this in a physically large layer could result in it being cropped to fit inside the bounding box.

12. Apply clay in strokes

Create a continuous brush stroke by holding down the Tool hand trigger

If you hold down the Tool hand trigger with the Clay tool selected and move your hand, this will create a continuous brush stroke. This can be changed by pressing the green gear icon on the Tool hand and selecting a single stamp at the top right of the panel. You can also enable line mode, which will lock the brush stroke along a line that protrudes from the Tool hand.

13. Define the shape of the torso

Use sphere and cube brushes to create the chest and abdomen

To begin creating the detailed parts of the robot we will make a start with the torso. Looking at the reference start building up the shape using the library of stamps at your disposal.

Make sure mirror is activated as shown earlier. Use a combination of the sphere and cube brushes to create the form of the chest and abdomen. To subtract parts of the model double-click the green gear button and the colour of the shape at the end of the tool will turn red. This will now remove clay from the sculpt and can be used to create shaped recesses in the sculpt surface.

14. Use the line mode to add bars

Lay down protective bars in line mode

At the bottom of the torso we want to add some protective bars. Use the cube stamp for a hard edge and go into tool settings and select the line mode. Lay down the bars and make sure they intersect where needed. Edges can be neatened by using the subtract clay mode in conjunction with the line tool to remove clay from the sculpt and to add a chamfer to the edges of that layer.

15. Utilise stamps

Try combining stamps to create interesting effects

Press the green gear button to bring up the Tool Options menu. There are a large range of stamps available, arranged by category. For this project we will mainly be using the Mechanical stamps. When using a stamp, the shape added will reflect the resolution of the layer you stamp it on. Try a range of stamps in add and subtract modes to create interesting shapes.

Next page: Finish off your VR character

16. Create the shape of the head

Build your robot head out of mechanical stamps

Make sure you have the head layer selected and pick some stamps that give you a cylinder and the rim for the shape of the head. Mechanical stamps are a great place to start for stamps of this nature. For the top of the head layer we use the subtract mode to create the hollow in the top. Use basic square shapes to add the grids at the front. This is best done with the 'single' brush mode.

17. Add shoulder pads

Put the shoulder pads in their own layer so you can position them separately to the arms

The shoulder pads can be created using some of the built-in stamps. Choose a shape that reflects that curved shape and apply to a new layer. This means you can position the shoulders separately to the arms. The shoulder pads on the concept appear to have a rough surface, so we can add the rough texture using a basic Clay tool with an organic stamp. Using the 'surface' mode found under the Brush Options menu, the brush can be applied directly to the surface of the model. The stamp will follow the surface normals. 

18. Define the shape of the arms

Change the brush size with the Tool hand thumbstick

The arms are made up in the same way as the rest of the sculpt. The best stamps to use here are still the Mechanical ones. Start by creating some cylinders using the line brush method to create the basic arm structure. Remember you can push forward or pull back with the Tool hand thumbstick to increase and decrease the size. 

Add a lot of visual interest with really complex stamps and make sure that the layer resolution is set high enough before adding clay in order to avoid rough or jagged edges.

19. Establish the shape of the hands

Model the hand separately from the arm if that makes life easier for you

The hands are made using a combination of stamps. Add a block of clay to represent the base of the hand. Add in lots of disk shapes to represent the knuckles and each finger joint, followed by small cylinders to represent each finger bone. Add a thumb on the side in the same way. You can split the model down further if you like and use the Cut tool to separate the hand from the arm. 

We only need to make one arm and leg as we will be duplicating and mirroring the limbs across the world axis.

20. Define the shape of the legs

Check to make sure your legs pose looks good from the side

The legs are comprised of very simple shapes, compared to the upper body. They are basically a group of cylinders with some complexity to add detail. Make sure when you are building them that you get the pose correct from the side. Adding cogs and wheel shapes among other greeble to the back of the knee gives the sense of a functioning robot joint.

21. Determine the shape of the feet

Adjust the position of the feet to ensure that the pose maintains balance

The feet of the robot are essentially a metal cage. Using a cube or square stamp, select the line brush mode. Begin to create the base shape of the cage, remembering to adjust the layer resolution as needed to ensure that the edges are crisp. Keep adjusting the position of the sculpt's feet to ensure that the pose maintains balance. To do this, select the foot or leg layer you wish to move, then using the inner grips of the controllers, you can move that layer around independently from the rest of the model.

22. Add high levels of detail

Use the Smooth tool to cover up seams and jagged edges

Once the shapes for all the layers have been defined, any additional details can be added, as well as sharpening any edges which are jagged due to low resolution. The Smooth tool can also be used to blend any seams together, where different brushes meet. Remember to make sure that layers don't clip due to bounding boxes shrinking when increasing resolution.

23. Photograph inside Medium

There are plenty of options for capturing images and footage of your sculpt

There are a few methods to capture images from inside Oculus Medium. You can capture stills, record video or record live scenes for playback in VR. These methods can be accessed by pressing the yellow control panel button on the Support hand. 

When capturing a photo or video, the camera can be locked to the sculptor's hand, to follow the headset or free float in the scene. This last method is useful as you can take multiple exposures of the same scene using different materials or lighting setups in a way that is similar to multi-pass rendering. These 'passes' can be combined to create interesting effects in Photoshop.

24. Paint and comp

Take lots of photos them comp them in Photoshop

In the Control Panel there is a Photo button. Lower the FOV to 0 to stop distortion. Lock the Photoframe to the world with the small Globe icon. Hit the Photo button to take a picture. Now move the lighting and retake. Keep repeating until you are happy. These images were brought into Photoshop where I composited them using the VR Photographs and layer blend modes.

25. Export for other programs

Medium can export in FBX and OBJ formats

The options for export can be found by pressing the yellow Control Panel button on the Support hand and selecting Export. The options include the ability to reduce polycount through a process called decimation, which involves setting a target polycount that the application will try to match. 

The formats you can export as are FBX and OBJ with the ability to export colours as a texture map or by vertex colour. With these options you should be able to export the file in a format that most software is able to read. 

This article was originally published in issue 228 of 3D World, the world's best-selling magazine for CG artists – packed with expert tutorials, inspiration and reviews. Buy issue 228 here or subscribe to 3D World here.

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