This is fairly long and dense post, but if you are still debating on which software to use I would like to share my insights with you. Of primary concern is what you need the software for. I did not see any mention of what you are actually using the software for. As was previously mentioned, Mudbox is a digital sculpt, paint, and texturing tool. Zbrush is best thought of as an all around digital design tool. If you are a technical artist of some sort than Mudbox may be more of what you are looking for. If you are a designer then in my opinion Zbrush is the obvious choice.
Many people say that Mudbox is an easier tool to learn, but I believe that this is merely a matter of perspective. Most 3d software packages have a standard setup for navigating the view port which is some variation of the basic camera manipulation algorithms that you learn in introductory computer graphics programming. In short if you are familiar with navigating in Maya, Max, Lightwave, Houdini, or even blender etc. than you have some experience with an interface that is at least similar to Mudbox. These are all tools that were designed by people with technical expertise for artists to use.
Zbrush followed a different paradigm. Zbrush was designed from the ground up with more input from the artist. Consequently, it has a unique interface. Many people find Mudbox easier to learn because it has a familiar interface. Truthfully, if you had never used any 3d software before in your life, I believe you would find the learning curve to be comparable. Comparing the learning curves of the two pieces of software is like comparing the learning curve between using Mudbox and Corel Painter. They are both digital painting tools with a small area of overlap, but they are fundamentally designed for different purposes.
MUDBOX as SPECIALIZED TOOL
Mudbox is specialized for a particular portion of the creative pipeline. In my experience, it works best if you have some preexisting model to start from that you need to add detail to. For example if you have a base mesh modeled in some other package and you want to lay in anatomical details, and or skin texturing and the like then Mudbox is more than capable. This seems more appropriate for someone working as a texture artist. When working in Mudbox you need not worry about generating the primary forms of the asset you are primarily concerned with secondary level of detail and higher (certainly you will tweak the silhouette, but you won’t be generating the main masses from scratch). Many of the other steps in the process are better handled outside Mudbox. You must construct custom base meshes outside of Mudbox, and you will also need to retopologize your geometry in an external program. On the upside Mudbox is intended to be a modular piece of the asset creation pipeline. I understand the new one even let’s you import skeletal information so you can pose your meshes based on the internal bone structure created by the rigging Technicall Director. The bottom line though is that Mudbox is a small specialized piece of the puzzle.
ZBRUSH as GENERALIZED DESIGN TOOL
Zbrush on the other hand is a one stop design shop. If you wanted to you could create 2d concept sketches and paintings all the way through to a completed sequence of 3D rendered images without ever leaving Zbrush. Most people, myself included would have no desire to even attempt such a thing, because there are other programs that have more robust tools for many of the steps in that process. Nonetheless, Zbrush is competent at nearly every step and it is best in class in some areas in my opinion. Zbrush is a design tool. It is intended to be used as a creative tool, not merely as a 3d sculpt/paint/texture tool. It can be used as such, but that was not how it was designed. Zbrush has as much in common with Photoshop as it does with something like Maya or 3DS. It is the closest thing on earth to 3D drawing as exists in the production ready product.
All of the fundamental artistic tools that designers and production artists learn can be simply and intuitively applied within Zbrush. Zbrush divorces designers from the technical constraints of creating production assets. A designer can establish gesture, proportion, line, form, value and color all without thinking about polygon budgets or UV mapping. It is possible to design characters entirely in 3D from the ground up in Zbrush. It provides a digital workflow that more closely resembles that of working in traditional media. You’re primary focus is on design. As a designer in most cases you will be providing finished high resolution images or detailed high resolution meshes for someone else to use to add detail to a lower resolution control mesh of some sort, which can be animated. Depending on the nature of your position you may or may not be the person that is responsible for the lower resolution mesh as well. Even if you are you can prepare it in Zbrush if need be.
OF DESIGNERS and TECHNICAL ARTISTS
In general I find that preparing production assets to be integrated into production is the job of Technical Artists. Designers are typically involved in pre-production and are fundamentally concerned with working out the concepts of how things should look and work in general. Their designs are typically passed on to various TA’s to realize as usable assets. Zbrush can be used in both cases, however Mudbox has it’s own advantages that make it more appealing for a subset of artists and designers. Mudbox however is far inferior from the stand point of a pure designer. I would also like to mention that I am aware that the roles of Technical Artists and Designers often overlap and the true definition of their individual roles depend on many factors that vary for each given working environment.
ME and MY ZB
I can open an empty zbrush document and in 15 minutes or so I can have a proportioned base mesh with all of the primary forms established with an elegant gestured pose ready for me to begin laying in secondary details. I’ll grant you that I didn’t start out being able to work that fast, but the point is that I can now. For Mudbox I have to create my base mesh elsewhere and that may take 20 to 30 minutes if I’m flying and all that is before I even export the mesh over to Mudbox.
I am much faster at laying out and sculpting basic form with Zbrush thanks to some of its tools than I am at box modelling. I realize that this is not the case for everyone. I found sculpting to be more natural so I honed my skills at it. If I need a usable mesh at the end then I just retopologize it later in the process. In general, base sculpting meshes aren’t suitable for animation or posing anyway. If they are, then they tend to be relatively well defined in terms of their primary forms, which is not good from a design standpoint, since the mesh is already dictating some of the features of its final form. For a texture artist this may be desirable.
YOUR A MEAN ONE MR. GLITCH
Someone mentioned the glitchiness of Zbrush. I tend to agree with his comments. At times I believe that it could do with more polish, but as a design tool, their is simply nothing else out their that does what it does. As far as the crashing goes. That is something that seems to be an issue with software like this. Programs like zbrush and many other drawing programs are limited only by your system resources. How many polygons you can display on screen at once, or how many pixels in the case of painter is determined by the amount of ram that you can dedicate to the program. If you don’t know approximately what your upper limit is you should find out. If you flirt too vigorously with the limits then you’ll crash the program if not your computer.
TAKE IT TO THE …
I’ve done it to so many different pieces of software over the years I’ve lost count. The bottom line is that you should save early and often with any of these programs. Some may seem more stable than others but you can push all of them too far. Due to the nature of Zbrush it gets pushed towards its limits more than most programs that I use. An accidental hotkey press here or there that subdivides the wrong thing, and boom there goes your session. You really do have to be vigilant when using features with zbrush. Getting very familiar with the documentation and forums is a must, because many features have rules and limits that are hidden away in the documents that aren’t mentioned in ztutorials and the like.
OLD DOGS and NEW TRICKS
Finally as far as learning new software goes, truthfully, if you set aside an hour a day for a week or two or just set a side a weekend or two to focus on learning the software and reading the manual you will master the basic functions in no time. I once taught myself mel script in a single weekend to meet a deadline for a school project, when a team member passed away, so that we could stay on schedule.
It can be done it only requires the will. Even if you are swamped with work now you won’t be forever. The reality is that in this field you must constantly be working on improving your skills and sometimes that means testing and learning new software. As I am sure you are aware software that is used on a regular basis must be mastered i.e. customizing work spaces and shortcuts for your own particular workflow to minimize wasted key presses and movements.
Hopefully, that did not seem like a rant, but time invested in the front end streamlining your process will save you 1000’s of hours of wasted time in the long run. If you shaved 5 sec off of an action you performed 10,000 times you would save 50,000 sec across those 10,000 actions. That is roughly 833 minutes or about 14 hours. Odds are you could get a good bit of work on an entirely new project done with 14 extra hours. I apologize for the tangent, but once you decide on which way to go it will pay dividends to learn the software properly.
I apologize for the treatise, but I believe there is a lot to be said on the subject. I hope that you read it and I hope that it helps.