Master medical visualisation
Learn the best way to render medical visualisations using X-particles and Cinema 4D with art director Farid Ghanbari
Top techniques from Farid Ghanbari
This tutorial will teach you how to create a medical visualisation in the 3d world. Before starting the project, we need to gather some references to make sure that the sizes of the cells are scientifically accurate. We will use cinema 4d and X-particles as our main tools to set up the scene and learn how to use X-particles to quickly create hundreds of sperm in a nice shape without dealing with each individual one. v-ray will then be utilised to light the sperms and egg with its powerful subsurface scattering material.
Choose the subject the most important purpose of a true medical illustration is to educate the viewer. it must be clear and scientifically accurate, paying careful attention to good design, organisation of content and where you are leading the eye. it also provides us with a vast array of subjects that we wouldn’t normally consider illustrating. the real-life microscopic environments that exist in our own bodies can provide inspiration for imaginative landscapes.
Create the egg to start the artwork, we need a nice egg shape as a base. Make a simple sphere in cinema 4d and change the type from standard to Hexahedron to get an even displacement over the entire egg. to add the details, you can easily put a displacer deformer and add a c4dnoise to its shader tag. Play with the noise type to get your desired details. You can also use layers and mask your first noise with a second one. sharper details need more segments in your sphere parameters.
Make the sperm since we have so many sperm, we need a way to create them instantly. X-particles allows us to do that easily. First, we need an emitter and an xptrail to see the emitter paths. second, we need an xpfollowsurface modifier to conduct particles to the egg. Play with the distance and pull to get your desired form. We can also play with variation to add a little variation to it and make it more natural. spend enough time at this level and ensure that you are getting the best result.
Work with xpsplinemesher once we get the nice follow path, we can start shaping the actual form of the sperm. thankfully, we don’t need to deal with polygon modelling to do that and here you will see the power of the X-particles plugin. Just put an xpsplinemesher and set your xptrail as its source. it will create the geometry instantly. From here, we just need to tweak the setting and play with the splinemesher spline curve to shape the sperm. You can follow your reference outline and play with spacing value and subdivisions to get the best result.
Add a little art to the science Because we are creating artwork inspired by science, rather than a purely instructional medical illustration, we want to go a little further and make it more interesting. of course, sperm in real world have a defined tail length but to create some nice details with thousands of tangled sperm tails, we can extend this. We can stop it wherever we want by setting different values on the lifespan on the emitter.
Create mood for the environment inside a real body, biological processes happen in total darkness, but that isn’t very interesting. our medical-inspired artwork needs an environment that we can relate to. Here, to create this mood the best option is the environment fog but to have a better control of it we need to create a Fog Box to control the amount of fog and its depth on the hero asset. this will give your rendering a nice depth and pull out your main hero to really emphasise it.
Secondary sperm as you may know, not all sperm reach the egg and there will still be a lot of them swimming in the fallopian tube after fertilisation happens. By having those secondary sperm, not only can we make our artwork a little more scientifically accurate, but we can also bring more depth to it and make a better composition. so according to our camera, we can put a few sperm pretty close to the camera to make an intense dof, and put some far away behind the egg so that they will be out of focus but still we can see them.
Start the lighting to start the lighting, it’s best to assign a v-ray advanced material and leave it on the default setting. We don’t want to mess with the materials at this stage. this helps you focus just on lights and make a better decision. sometimes different colours, reflection and specular can be distracting and slow down the lighting process. as the first step, we just put a v-ray dome light with low intensity to see the whole scene with even lighting and no harsh shadows.
Key light, different experience the majority of the egg and sperm will be illuminated by the key light and so this light has the most critical role in our lighting. spend enough time playing with different angles and moods. set your render sampling to progressive with a low-resolution image size to have some quick test renders that you can compare with. We can also try various directional numbers in the v-ray light to have different brightness and harshness of shadows.
Volume light the fog doesn’t work by itself but the combination of the fog and one volume light could make a stunning background. to establish that, create a v-ray spot light and put it behind the egg. You can keep playing with this to achieve the best results. inner and outer angles play the biggest roles in getting a nice gradient in the background. You can also add a little bluish or greenish tint to your light to make it more interesting.
The colour palette once we get a decent basic result with our lighting on a simple grey material, we need to assign colours to see how it works. at this stage, we recommend that you add sss to your materials, since it affects the lighting a lot. You can play with the simple colours to get your desired colour palette, then create details like bumps, displacements and dirt. Because we are doing a science-inspired project instead of a truly scientifically accurate illustration, we can let our imaginations run wild with crazy colour schemes. But knowing what colours your subject would have in the real world can help create your palette, and this will make your artwork more consistent and easy to read.
Because we are doing a science-inspired project instead of a truly scientifically accurate illustration, we can let our imaginations run wild
Rim light When you use subsurface scattering Materials, the rim light is one of the key factors to work on, just like the key light. sss materials use the lights that come inside them from the opposite side of camera angle so try to put these in the best positions to achieve the most satisfying scattering effect. You may need to play with sss parameters such as scattering radius, subsurface colour and overall colour at the same time. don’t forget to try different tint colours on your rim light.
Final tune at lighting You will always need to redo some work during the process, whether it be textures colours, lights or even slight changes to the models and positioning, and this is completely normal. at this stage, look over your rendering and try to just tweak it to get the most satisfying result from your vision. turn your lights on and off separately to see how they work with your scene.
Set up the render setting thankfully, v-ray for cinema 4d has made everything a little easier for users – you just need to take the most care with your sampling. For this render, use Bucket type for sampler with 0.004 threshold. set the Max subdivision to 100 and put the Min to 0. don’t forget to enable ambient occlusion, which comes under indirect illumination. since we have created a v-ray Fog Box, you don’t need to turn on the environment fog in your environment tab.
Render passes to create your render passes in v-ray for cinema 4d, you need to open the v-ray multipass Manager window from the main v-ray Bridge tab. select your desired passes and make sure that they are all checked. now you just need to add a post-effects pass on the multipass menu in your cinema 4d render setting window. Here we have created different object id and the Z-depth pass to have more control at post-production stage.
Apply DOF Without depth of field, we would have a boring, flat image. in the real world, we would only be able to see these tiny cells through a microscope. Microscopes have a very shallow depth of field so in homage to that, using depth of field as intensely as possible can help represent that. Here we have used lenscare’s Frischluft plugin in after effects to achieve a nice depth of field. But no matter what software you prefer to use, since you have an accurate Zdepth pass, you can use it in whichever application you happen to be most comfortable with.
Post-production since we did the most of the rendering in-package and we now have a nice-looking result, we may need to do just a little colour correction but there are no big changes in post-production. the only things we will add to our image at this final stage are the clouds. For this, you can simply find some PNG files online and put them close to the egg. Besides making your rendering more artistic, they will give an unexpected sense of scale to surprise and delight your audience.