Use Gravity Sketch to create a detailed robot design with Glen Southern’s step-by-step guide

Glen Southern demonstrates how to create a detailed robot concept in Gravity Sketch

Ioften use VR to rough out designs for a new project. The sketching tools make it very easy to block out my ideas in 3D and then build over the top of those strokes in another layer. It is a very effective way to plan out a design, but with Gravity Sketch I can take it one stage further. I not only sketch the design and block it out for overall shape, but I can add surfaces and more recently polygons with full-on subdivision surfaces. These models can be exported as an FBX and I can use that geometry in other programs, either for rendering or in some cases for the actual animation. In this tutorial and accompanying video I will work through a session to make a robot with a complexlooking design and use that in Cinema 4D with Redshift to get some very striking renders. I will show you how to sketch out the robot’s overall shape, and how to then block it out to make sure that the volumes and silhouette read well as we rotate the model. I always break the model down with separate materials as these sets can then be used in Cinema 4D to quickly isolate parts of the model and then assign the correct materials and maps.

01 FREEFORM SKETCHING

We won’t use any references for this design as it is sometimes a good idea just to play with shapes and ideas and see what emerges. I had an idea to create a robot that is like a centaur but essentially the body plan of a spider. To begin with I just use the ink or stroke tool and start with symmetry switched on in the main panel so I can work on both sides of the model at once.

02 STAGE FLOOR

When you are designing a creature or something that has to function in the real world it is useful to have a ground plane with the model so you can line the feet up exactly with the floor. Also you can see if you are getting the centre of balance correct as you work. In Gravity Sketch it is called a ‘stage floor’ and is accessed from the main menu. You can have either a rectangular stage or a round one and it will scale up to suit the size of your model. We often turn it off once we have established the feet position.

03 ROUGH OUT THE DESIGN

As we are not using any reference it is okay to scribble in the air to try and find some shapes that work for the design. I often lay down lots of strokes that I don't need but it helps me to find the shape I want. At the start just block out a body of some kind and work down from there, adding an abdomen. The bottom half can be more spiderlike and the top half can be like an upright man.

04 DEVELOP THE SKETCH

The sketching part might look a bit confusing at first so keep rotating around and trying to see how the robot will look once it has some body paneling. The sketch will not be used other than as a guide to start more detailed modelling, so this part is very creative and free flowing. Try and approach this section as a sketch artist rather than a modeller and keep your lines thin and sketchy. If you do this bit well it should only take you a short amount of time to get a design you like. Don’t forget the red button for undo.

05 LAYERS

To use Gravity Sketch to its full advantage you need to start using layers to break down your model, accessed from the main menu via the layers icon. The sketch is on one layer and the rest of the model will be placed onto new layers as needed. That way the Sketch layer can be made transparent and then used as a reference. Layers can be locked to stop you accidentally changing anything.

06 VOLUME TOOL

The next tool to use is the volume tool, which enables you to make a chunk of geometry that you create by firing the trigger on the dominant hand and moving your hand along. You can't get very complex shapes, but if you create multiple shapes and combine them you can make the volume you need. Use this tool to block out the shape of the robot in a more defined way than the sketch.

07 GROUPING

If you have a few volumes that need to be combined together simply increase your Grabber size (thumb stick forward) until it covers over the parts you want to group. Then on the non-dominant hand hit the purple group button. Repeat the process until you have a full leg grouped into one. You can ungroup them by hitting the purple button again.

08 GROUP THE LIMBS

You can pick up the entire leg as one group and using the trigger on the dominant hand you can add multiple legs to the model. If you have symmetry on you will of course be making the left and the right legs at the same time. We will be adding more detail to the leg, but it is good to have them laid out like this as you are working. If you want to repose a leg you can ungroup it.

09 DYNAMIC POSING AND OVERALL SHAPE

At this point you can start to improve the dynamic posing of the robot. Make sure that the model is sitting on the studio floor correctly and that none of the legs are poking through the floor. Move them around to get a sense of weight and purpose for your design. You can easily work out your poses at this early stage before you begin to add the more detailed geometry. As you add new meshes you can start to delete any of the volume tool parts that are no longer needed.

10 REVOLVE TOOL

To start making more mechanical parts we can use some of the other tools on the non-dominant hand. The revolve tools allow you to lay down points that are then revolved around an axis, creating cylindrical shapes. Depending on where you lay the points you can make wheels, pipes, disks etc. For this robot we will make a set of shapes to use as joints. Click on the settings for the revolve tool and use ‘point mode’ – that way you can easily control the shape with single clicks. Make several types of cylinders and disks to use together.

11 TOOL PACK

As you make the shapes, you can create a kitbash set to enable you to make all the joints and hydraulics on the models. Start to put them off to the side so you can pick them from the pack as needed. Make some pipes and change their colour so we can identify them as different from the cylinders. Put several parts together to form a hydraulic arm to use on all the legs.

12 CONSTRUCT THE LEGS

With all the tool parts you can now start to create a full leg. Think about how you want to join the legs and then put together a joint from the parts you just made. Add in some pipes for the leg extensions and then add the hydraulics to the legs as needed. You can get a really cool effect simply by repeating the parts you just made. Make sure you look at some spider references at this stage as you want the legs to be joined as a real spider’s would be.

13 VOLUME TOOL PLANAR

If you click on the volume tool icon and go into its settings you can activate Planar mode. This means that as you lay down a stroke or points it will make a flat surface from those points. This is a great tool for constructing flat panels and parts to be made up into a more complex model. Use this tool to make parts for the legs with gaps in the middle.

14 COMPLEX LEG SHAPES

Because we now have a tool pack and a set of flat shapes we can construct a complex leg assembly. We are going to use this leg many times so we need to make it very detailed. Add revolved cylinders from your joint pack and make up some detailed sets to repeat across the sections of the leg. Make the leg thinner as you get towards the end. Add small cylinders for detailing.

15 DUPLICATION

Once you’ve added enough detail to the leg you can look at duplicating it across the whole model. For this design I wanted four legs on each side with the back four being planted firmly on the ground. The next set would be facing forward and the final set raised into the air in a strike pose. I decided to add two more on either side of the head which would act like pedipalps on a spider. This would make the head more imposing in the renders. To duplicate simply pick up the part and use the trigger on the dominant hand.

16 POSE THE FRONT LEGS

I wanted the robot’s pose to be likened to a spider when it goes into a threat posture and raises up its front legs as if in readiness to attack. I scaled the front pair of legs up and then angled them in such a way as to look like outstretched arms. Remember if things aren’t looking good then ungroup all the parts and re-arrange them to suit. Group them back up again after.

17 MATERIAL SETS

When we eventually export this model from Gravity Sketch we will want to break it down into sets and then even further into different material groups. We do this so that we can quickly apply a new material to all the relevant parts. For example, you might want to make a chrome material and apply that to just the nuts. To do this add a new material (Panel on your dominant hand) to a model and that creates the material for you. Now apply that material to anything you feel is the same.

18 ADD CABLES

I have a bad habit of adding cables to everything. For this type of model the cables hide bits that I don’t want to see in detail. I added cables around the leg joints, the hydraulics, the body around the spine, under the ribs and anywhere that needs the visual interest. I try and keep them in sets, so the leg cable can be grouped with the legs for example.

19 FANGS

I added fangs to the front of the model using a subdivision cube. Click on the primitives menu and then highlight the sub-d button on the top right. Now click a cube on the left and a subdivision model is created. Move that to the fang area. Click on the blue button on the non-dominant hand and you can enter the sub-d edit mode. From here you can manipulate the points, edges or faces of a model. Hover over an edge and fire to add edge loops. Pull the fangs down to make a sharp point.

20 MAKE THE HEAD AND EYES

Create the head with a subdivision cube. Once you have put the cube in the scene, bring them to the centre of the world and they will snap together (when you have point mode activated). Now use the point mode to shape the head and leave a flat area on the top. Use the primitives panel to add a sphere for an eye. Make it black and then duplicate it to add eight eyes, four each side.

21 SMOOTHING

To make the head mesh smooth, first of all you can activate subdivision smoothing. From your non-dominant hand you can call up the Sub D panel. Activate Sub-d and set it to 2 to make the head very smooth. Now in point mode with the Grabber covering a selection of points, pull on the thumbstick to smooth out the points even more. Be careful around the centre line as they may snap together where you don’t want them to.

22 CREATE THE BODY

For the robot’s body we can repeat the same process we used for creating the Head model. Simply start with a subdivision cube, then snap it to the centre to make it symmetrical. Now you can grab faces and use the trigger to extrude out and down. Do this until you have the core shape and then add more edge loops to define the edges. Smooth out the body and then add some extrusion down the spine area. It’s important to try and establish an interesting silhouette.

23 ABDOMEN

The abdomen can be kitbashed. Make up some interesting parts using the volume tool set to Planar again. Create some interesting railings and repeat them around the core shape. Now use the default volume tool and make some interesting blocks to build up the overall look. Make a new material and add it to all the abdomen parts so we can isolate them later.

24 FINISHING TOUCHES

Now it’s time to take a look around the entire model and add any finishing touches before we export. Add extra cables to hide anything unsightly. Remember this is a concept model so you are not trying to make it completely perfect. Tweak the position of the legs but make sure none of them are popping through the floor. Add more detail around the eyes and face if needed.

25 EXPORT

Before exporting you can grab each section of the model and move it away from the main body. That will make it easier to isolate in the render program. On the non-dominant hand navigate to the save menu and use export. Set it to OBJ and make sure the mesh is set to Control, not Mesh or all of your Sub-d model parts will be super high res on export.

26 IMPORT INTO YOUR RENDER PACKAGE OF CHOICE

I decided to go with Cinema 4D here, but you can choose whatever program you are used to working with, such as Blender, Maya, 3ds Max etc. As the model was pulled apart before we exported it, it is now easy to group and texture. The selection sets have been made from the materials that were assigned, so you should be able to select all items with the same material, and then apply a material to them all with ease. Break the model down into logical sets and begin adding the materials, then texture in your preferred way. I textured this model with Photoshop. •