Using Houdini in Game Development Workflow

3d artist Michael Bitsakis talked about the way he uses procedural technology in his 3d workflow. He describe some of the ways you can implement Houdini software into your Unity 5 tech. Interview recorded & edited by Kirill Tokarev.

Introduction

I am Michael Bitsakis. I’m from Greece. Currently I’m working for Pixolabs based in Shanghai. My main line of work is 3D art and design. I started back at 1996 as a hobbyist and in 2001 I graduated from Private College for Industrial Design and CAD interior / Exterior Modeling. At the same time I was studying to become a mechanical engineer and working in several architectural and advertisement Studios in Thessaloniki, Greece .

From 2008 to 2012 I had my own animation studio, doing mostly games, interactive Unity visualisations and 3d animated videos. Some of my clients include Hitachi, Panasonic, Microsoft, Sony.

I enjoy working with Pixolabs. We specialise in Virtual Reality (VR). We have an international and multi-disciplinary team of creative and technical talents passionate about VR. We work with clients in a wide range of industries and deliver VR showcase for products or facilities, as well as games and interactive training. It’s an end-to-end service – from the VR concept, through planning, development, deployment and maintenance of the equipment.

Benefits of Procedural Tools

Trapped with traditional and destructive modeling, rigging, animation and VFX for many years I was searching for an alternative solution, a solution that would allow me and my team to provide our clients with fast revisions at any given time.

Thank God we found Side Effects (Houdini) , Allegorithmic (SD , SP and B2M ) and PILGWAY (3D Coat).

At Pixolabs I make full use of all those powerful procedural tools. For example, with Houdini I create and model, rig and animate everything procedural, all my VFX too of course , absolute freedom in an non destructive way.

Once we are done with the final modelling phase and revisions I get into Substance Designer building the basic procedural materials. As production moves on each substance materials evolves with it. With traditional painting and even 3d painting that would be a total disaster! It would require us to paint and repaint everything from scratch.

With substances ready we either apply them as they are with all the procedural properties on our assets or I export the textures and create smart PBR materials in 3D Coat for hand painting. Substance Painter smart materials and Quixel photo-scanned materials are used too for hand painted assets, they both work extremely in this section I must admit.

Using Houdini with Unity 5

When we have all the stuff ready, we import them with Houdini Engine as digital assets or fbx into Unity 5. Substance materials get imported as well. Same applies for the painted PBR textures from 3D Coat , SD and Quixel. From scratch to finish we view everything in Unity.

Houdini literally saved us here. With this piece I have turned a chair into a table in a matter of minutes inside Unity Adesert level could be changed into a snow level with unlimited iterations in hand. Again, all this happens straight in Unity. All rigging and skinning are perfectly transferred with fbx export or Houdini engine into Unity 5. I have never faced a serious or show stopper issue so far.

There are times when a character needs a prop attached and skinned on the main body mesh. With traditional tools this means at least re-rig / re-skin and doing all the animation from scratch. This is not the case with Hounidi! New bones can be attached on the existing ones without braking the skin procedure and if something needs a fix with edit capture weights and regions we are safe one more time.

Procedural levels and assets change / alter into Unity even in realtime when we export as digital assets and used with Houdini Engine inside Unity. This is a huge time saver. Plus I can get revitions on the fly as my superior can also change / alter the exact same asset realtime. With Houdini I can start from a clear file, model, rig with pre-made bipeds, skin, uv unwrap, motion capture or traditional animate, do my characters hair styling – all procedural. Possibilities are just endless.

Doing Procedural Stuff in GameDev

As we all know a game development / production goes through many stages. Each one of those stages require revisions, back and forth communication between artists, levels designers, sculptors, painters, concept artists and the list has no end.

Mistakes from misunderstanding, miscommunication, sudden changes on production plans and concept sketches – it’s a real nightmare, when working with traditional tools, cause you have to redo everything from scratch again and again. With Houdini you have everything in your hands available at any time, active and most important non destructive with realtime procedural properties on!

1 person 10 assets, medium to advance level, model, rig, skin phases done in 11 working hours, fully unwrapped and textured (SP and 3D Coat) and tested in Unity. Revisions included for each model.

Everyday I do about 6 or 7 from scratch to end asset models in 11 working hours , many times I even have time to test new techniques and evolve even further.

I have even used voxels sculpts from 3D Coat inside Houdini in order to perform re-topology and sculpt some forgotten details (yes you can also sculpt in Houdini as well).

Of course on a pro level we do need more and more of those wonderful tools. More modeling tools (Houdini 15 had a good amount of new tools but we do need more). Better, faster integration with Houdini Engine and Unity is a must as well, especially when poly count goes a bit higher than expected. And of course, I want Houdini VFX into Unity. At least where it’s possible.

Using Houdini for Modeling

For low poly modeling with Houdini one of my personal favorites was the Case 2388. It was done in 1 working day, modeling and unwrap (11 hours) and painted in the next half day with materials from Substance Designer and hand painted into 3D Coat. A sculped version and normal details were also created in 3D Coat in order to bake on the original Houdini low poly base.

Modeling in Houdini works more or less just like in any traditional modeling software out there. You start with the existing techniques (Box/Subdivision Modeling for example), edge, vertex, face move rotate and scale, move on with modifiers, deformations for rough model if needed, then again move on to polygon tools, extrude, bevel, polybridge, loops etc. Moving towards the final model.

So far the same or similar workflow with traditional modeling with a big difference – THE NODES. For each step you do a node is created for you. You can go back at any time and alter one specific node. If this node has linked with expressions with another part or node those will work and change together. Of course one change in a simple node can also change the overall model without the use of expressions (up to a point to be precise) and here is the magic if you find expressions a bit hard to follow right on start.

Low poly modeling was never an issue. High poly works fine as well. Artist can even move from low to high poly and visa versa with subdivision nodes.

Unwrap can easily be done with UVunwrap, flatten , fuse and edits where needed.

This is the first part of the interview with Michael Bitsakis about procedural tools in 3d production. In the next part of the article we’re going to discuss new way to use Substance Painter in conjunction with 3D Coat.

Michael Bitsakis, 3d artist