There are a lot of 3d software programs available and at a glance it can be hard to understand what will meet your needs. 3d models for games have a more specific requirement than that of models meant for rendering images or movies due to their requirement to be real time rendered. When investigating software such as Zbrush I’m sure you will have a mountain of questions and the first being can Zbrush produce models for games?
Zbrush can absolutely produce models for games. It is a popular choice in the industry and is widely used in a game 3d modelling pipeline. It has the ability to export to OBJ or FBX formats which is the standard format used in game engines for 3d models.
Zbrushes sculpting features can sometimes result in large amount of polys. Some preparation of models before importing into a game engine may be required to assist with real time rendering workload. In this article I will outline what steps specifically are required.
Who Uses Zbrush
A lot of studios and professionals use Zbrush for game modelling as it gives a lot of versatility to sculpt. It can model game characters and props in a way that traditional software such as Blender or Maya cant.
If your just getting into modelling or are considering Zbrush please check out my article here outlining the advantages and disadvantages of Zbrush.
What Can you Do with Zbrush
Zbrush specializes in the 3d modelling process. It can be used for what is referred to as sculpting and box modelling. It has the ability to texture and retopologize, however it cannot animate.
Zbrush is not a replacement for software such as Blender it is a tool that specializes in modelling. A direct comparison to Blender is not possible as they programs differ in the tasks that they can perform. I personally have had the most success using the two programs in conjunction with each other working to their strengths.
Preparing a Zbrush Model for a Game
While you could technically simply hit export on any model you create in Zbrush this may not be the best choice. If you utilize Zbrushes sculpting ability there is a very good chance you will have a poly count in the millions. This is not ideal for a real time rendering engine rendering at 30 to 60 frames per second. Your game simply will struggle to handle the computation required to render the model.
This is why you will likely have to have to take these two steps to export your model from Zbrush.
- Retopologize your model to a low poly version
- Use normal maps to fake the details
Retopologize your Model
Retopology is the process of recreating the models mesh so as to reduce the number of polys. The retopologized version has less polys than the original and hence has less detail.
Zbrush actually has ways you can do this in fact there are five. These range from fully automatic to fully manual. You can find an article I wrote on this outlining them all here.
Creating a Normal Map
A Normal Map is a texture you can apply to your model that in a way fakes the details of the high poly mesh. This map emulates the way the light reflects off the model giving it more detail than your actual model does. Most game engines will have the ability to use this map as it is an essential part of the 3d game development process.
In step one you reduced the number of polys and hence reduced the amount of detail, so a Normal Map is now required. Unfortunately Zbrush does not have the ability to do what is referred to as Baking a Normal Map. Blender has this capability, however I’ve not always been impressed with its results. If you are looking for a free piece of software I highly recommend xNormal it does a great job and is easy to use.
Zbrush File Types
As I have already mentioned Zbrush has the ability to export to common file types such as OBJ & FBX. These files are the most common files used in most game engines for models. This means anything you create in Zbrush has the ability to be exported into a game engine.
Zbrush also has a native file type called ZTL or as referred to in Zbrush a Zbrush Tool. This file type can only be used in Zbrush so any attempts to use this file type in game engines will be unsuccessful.
If you are unfamiliar with the differences of OBJ and FBX files the key points are as follows.
OBJ: Obj files are typically for static models meaning they are simply the model. There is no extra information such as animations. This file type works best for props and anything that is not going to need to be animated.
FBX: FBX can store additional information besides the model itself. Of particularly of importance for games is animations and a character rig. This file type works best for characters who need to be animated
Can Zbrush Models be Animated
You can absolutely animate a Zbrush model as previously mentioned Zbrush exports both OBJ and FBX formats. While Zbrush itself does not support animation you can import it into a program such as Blender or Maya to animate and from there import it into your game engine of choice.
I know what your thinking, yes it is inconvenient to have to use multiple programs but believe me when I say, there is simply no one single program that is perfect at all aspects of 3d.
Is Zbrush Free
Unfortunately Zbrush is not free you can check the prices here. Zbrush have released a less feature rich version of Zbrush aimed at indie developers called Zbrush Core. This is about a quarter of the price of the full version but definitely something to check out
If you absolutely have no free cash to spend, I’d highly recommend you try Sculptris. This is a piece of software developed by Pixologic the makers of Zbrush with the same sculpting ability as Zbrush. Be aware however it has a considerably reduced feature set and is no longer supported so you may have mixed results getting it to work. Though it is no longer supported it is still a really good piece of software and free to use for commercial purposes.
Conclusion
Hopefully now you understand that Zbrush is quite capable of creating models for games and if you’re thinking about trying it out I encourage you to give it a go. It’s a fun program to use and has assisted me greatly in my game development endeavours. While it does not have all the functionality you may need, its modelling abilities more than make up for its shortcomings.
Good luck and happy modelling!!