Car Render Challenge 2023 - Buggy Race
Hi everyone, my name is Josh, I’m a 3D artist originally from England but currently living in Amsterdam. My idea for this project is a little weird but I do imagine it will be an interesting model to create, I plan to make a very small “Bug”gy powered by snails… I knocked up a concept that I quite like, based on a tubular buggy chassis but with twig-based shapes that could be found in nature.
Step one is to create the twigs. I will be using Houdini for the vast majority of this project and generating as many things as I can procedurally. I am still a bit of a beginner in this program so this contest is a good push to lean some new things. I created a tool to create twigs from curves, it generates a low poly version and a high poly version complete with vertex colours. With an integrated python script the 2 versions are exported from Houdini, then batched through the Substance Automation Toolkit to bake the high res colours and height details onto the low poly mesh, resulting in customizable, completely procedural twigs for the chassis. There are a lot of assets that need to be created for this project so I will try to automate as much of the process as I can to make the computer do as much work as possible for me in the limited time available.
Here is a little insight into how it works, the most logical way to do this in my opinion was to always work in the same axis, Y in this case, build a straight stick based on the length of the input curve, then deform it back to the desired shape. This is done mostly using VDB’s and volumes, then the texturing is done with noises in VEX and some tri-planar projections in VOP networks. The whole thing runs in a loop so the 2-curve type sticks are made together as one mesh
One of the more challenging parts of this was to make sure the 2 sticks lined up with each other, there is a kind of bump that needs to be modelled on the first stick for where the second one grows from, so the orientation had to be pulled from the second line within the first loop, deforming the line and calculating the orient from the first point on the second curve did the trick here, I have avoided using quaternions in the past as I find them very confusing but this helped my to understand them a bit better
I created all the curves needed and batched everything overnight, there are 36 different sticks in total so this was a massive time saver. I added random seeds to a lot of the parameters in the tool so the colour and shape of each stick is unique.
Next up was the leaf springs, Similar approach, procedurally generate a high and low poly leaf, then bake the textures. I added some controls to bend the sides of the leaf but it is again generated on one axis and then path deformed to the input curve. These were again batched overnight
Now I needed to tie the sticks together, I had an idea that the car will be driven by a spider so spider silk will make a nice way to lash everything together. I originally considered using the vellum solver to create some shrinking ropes around the joints but this seems a little overkill in this situation, and procedural shapes will solve much faster. All we really need to do to create ties is to circumscribe a shape around the geometry. Houdini has a great shrink wrap node to do things like this so that was a good start. Again I made a tool to create the silk from an input circle in this case, the position and angle of the circle starts a loop which randomly rotates and moves on each iteration and wraps a bunch of lines around the geo
Some additional noises and wires inside the geo creates a nice web-like look
Next up I need some snails to power the thing, I started by poly modelling some base meshes in 3DS Max for this, then moved them into zbrush to sculpt the details, the topology on the shell was tricky to keep as quads but I managed in the end.
I also need a driver, I decided on a jumping spider in the end, lots of legs will help hold the frame and the little arms can be used later to add some reigns to the snails. I've also wanted to make a spider for a while since I saw the incredible Samsung advert so this is the perfect excuse to get started. This was modelled solely in zbrush, I started by blocking out the shape and basic anatomy with zspheres, dynameshing it and slowly adding the details, then when I was happy with the overall look I retopped with zremesher and began sculpting the finer details to bake in later on
A fantastic concept so far Josh.
Another update, I assembled the car and gave it a bit of a rig so I don't have to manually pose the snails or axles, it works by projecting points down onto the terrain and deforming a skeleton based on the returned positions so they follow the contours of the ground
Beautiful progress, i can already tell that the final render would be definitely high end feature animated film quality !
some more progress, the deadline is close now so I have to get the environment sorted. I made some procedural assets for scattering, adding variations to some attributes by seeding them with the current frame number. Here is some moss made with l-systems
I have some renders now so time to wrap this project up, you won't see until I post the final shot but I have gone for a very fantasy style forest with lots of glowing spores and mushrooms, this wasn't made with one render but rather 8, I set up some takes in Houdini for this as I want to make a lot of volumetric passes and lighting that just isn't possible in one take. I also set up some quick dust trails with the pyro solver so I can add a bit of movement to the image. The texture on the ground near the camera is a little ropey but that will be out of focus in the final shot.