Reviews

3dworldmag.com094 | | Christmas 2010

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About the author Scott Spencer has worked in the effects industry for 15 years as a

physical and digital creature and character designer. He currently works at the Weta Workshop. He’s also the author of ZBrush Character Creation and ZBrush Digital Sculpting: Human Anatomywetaworkshop.co.nz

SoftwareTexture-painting application

ari is a 3D texture-painting application developed in-house at Weta Digital. Weta continues

to maintain a development team working on the program (which, in the interests of disclosure, I’ve never been a part of – Weta Workshop is a separate company from Weta Digital), while The Foundry handles all the commercial aspects.

One of the most appealing aspects of Mari is the fact that it was developed in a production pipeline by artists on real deadlines. Many applications are developed in a vacuum, with beta testing happening outside an actual production environment. Because of its development history, Mari has obviously been put through its paces and pushed to the limit long before it was commercially released.

It’s apparent after a short while working with the program that real-world concerns and workfl ows have informed the design of the application. From the interface to the speed and ease of use of the tools to the plentiful tool tips in

This production-tested texture-painting application is both powerful and elegant, says Weta Workshop’s Scott Spencer

Mari 1.0

PRICE• £600 / $956 / €686

PLATFORMWindows / Linux

MAIN FEATURES• Buffer-based system

enables strokes to be edited before baking to texture space

• Textures can be viewed on animated models

• Comprehensive brush toolset for smearing, cloning, warping etc

• Healing brush for UV seam removal

• Advanced masking engine

DEVELOPERThe Foundry

WEBSITEwww.thefoundry.co.uk

unsure about what something does or how it works. It even tells you the varioushotkey combinations for each tool, which helps you to get up to speed quickly and fl attens the learning curve of the program.

Maya users will immediately feel at home with the navigation. Mari has incorporated a unique marking menu-style tool called the Pie Tool. This is a custom menu tool that provides you with a Maya-style marking menu with common brushes, colours, textures, and tools saved in quadrants. I’m a big fan of marking menus like this because they lend themselves to a gestural working style that encourages speed, and it keeps the interface out of the way while you work.

the HUD, Mari strikes me as an artists’ tool conceived with the demands of production in mind.

Upon receiving my seat of Mari, the fi rst thing I noticed was the ease of installation and licensing. The license key is simply dragged and dropped into a licensing program, which automatically sets up all the necessary fi les and folders. It couldn’t get more simple than that.

FIRST IMPRESSIONSOn running the application for the fi rst time, I was struck by the clean and streamlined interface. The display is uncluttered by palettes and options. It appears that the tools have been sensibly distributed throughout the interface in logical locations. Elegant was the word that came to mind as I continued to explore the quick-start tutorials and gota feel for just how clean and well-designed the program is.

Nearly all the tools have a tool tipthat appears in the HUD, so you’re never

M

(Top) Shader tools let you alter the material specularity. (Above) Viewingthe ambient occlusion render layer

Mari 1.0

Here the PaintThrough tool is used to apply a skin texture rather than paint one from scratch

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Menu layouts are fully customisable, and palettes can be dragged and docked to suit. The camera settings in Mari are customisable too, with perspective, orthographic and UV views, and any time you need to swap to a specifi c orthographic view, you simply press the corresponding number key. Other default hotkeys will also make sense to the average user: [+] and [-], for example, change the brush size, while [B] bakes textures onto the model.

MULTIPLE TEXTURESOne cool element is a disk usage baralong the bottom of the screen that shows how your resources are holding up. Mari is intensive on hardware, and it’s desirable to keep an eye on your disk usage as you work with multiple large texture fi les. The Mari workfl ow has been tested for hundreds of 4K textures active at one time, and you can work with hundreds of UV patches on a single model.

In terms of poly count, very dense models can be loaded and painted – in fact it’s possible to handle models containing over a million polygons. Importing takes place as a background task so you aren’t locked out of working while you wait for the computer to catch up.

So how does Mari work, and what makes it a unique texture-painting tool? Mari isn’t a 3D painting program like ZBrush; your brush doesn’t follow the contour of the model as you paint directly onto its surface. Instead, Mari is a hybrid projection paint tool, which gives it an enormous amount of fl exibility and strength in its workfl ow. As you paint in Mari you’re applying strokes to a ‘paint buffer’. This buffer is like a 2D view plane that sits just over the model until you bake it down. This means strokes can be applied and further edited before being applied to the model. Various texture tools can be used on the surface, and each stroke can be manipulated with the various other tools before the colour information is baked down into texture space. This baking can be done manually or automatically as you rotate the model to a new view.

The paint buffer remains editable until it’s baked onto the surface. The process of painting and baking is so seamless it really feels like you’re painting directly onto the model while rotating around it in 3D space. There’s no sense of the drop, paint, pick up and repeat workfl ow you get in some other 3D painting

applications. Any edits you make to the paint buffer before you bake it are applied to the strokes before they are applied to the model. For example, the Spline Warper tool is a lattice-style deformer that enables you to deform the stroke or image projection by pulling lattice points. The density of the grid is fully adjustable to higher and lower resolutions as you work by pressing the arrow keys. The grid can be redrawn as many times as you like by simply drawing a marquee.

Some of the paint tools I found particularly useful include the PaintThrough tool, which enables you to load a photo reference image and paint through it, applying the image to the model surface; the Healing Brush, which enables you to remove texture seams;

and the Slurp Brush, which smears and smudges your brush strokes. Mari also includes a Clone Brush, which works both on the paint buffer and the baked texture. All the brushes work in 3D mode as well as fl attened UV view.

Some tools seem designed to address common workfl ow issues and annoyances that are far more diffi cult to deal with in other programs. One such tool, and a

“Mari isn’t a 3D painting program like ZBrush – your brush doesn’t follow the contour of the model”

»

Mari REVIEWS

The Blacksmithfi les contain several channels that include diffuse colour, vein colour maps and masks to isolatethem from the main diffuse map, bump and specular maps

The brush manager enables you to alter and create custom paint brushes

You can paint in 3D or in the UV view. This model was UVed in ZBrush using UV Master, then exported to Mari for texturing

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3dworldmag.com096 | | Christmas 2010

REVIEWS Mari

personal favourite, is Edge Masking. When projecting an image down an axis you may fi nd that the image stretches and bleeds around the edge. Mari gives you visual feedback of what will be painted and what will be masked: grey areas are paintable, blue areas are masked. This masking is projected down the Z axis, and updates in real time as the model is moved. This helps you to maintain a clean texture and avoid the stretching artefacts that often result from projections.

PAINTING IN CONTEXTPainting works across multiple objects – Mari calls this ‘painting in context’ – so you’re able to paint objects in relation to the environment in which they will be found by pulling in all the scene elements and textures at once. Background plates can also be loaded for reference. This saves time and effort because all the textures can be evaluated and adjusted together rather than assembling the scene later and noticing inconsistencies that need to be corrected.

One of the most attractive aspects of Mari is its ability to import animation data, which means you can see your model move, and correct the texture at keyframes where stretching or distortion occurs. Needless to say, the animation functionality greatly streamlines the

process of evaluating and correcting textures in an animation pipeline. It’s also possible to paint animated texture maps directly in the program on a frame-by-frame basis.

Many of us have had the experience of trying to share fi les across a team and discovering that core assets are missing when we go to load the project. This is a major annoyance and far too common an occurrence. Mari has a function to help reduce or eliminate this problem altogether when working with teams: archiving enables you to save the model, textures and all pertinent scene elements to a single fi le.

When I fi rst tried to launch Mari, I found I was running into a consistent technical issue when loading fi les. I sent an email through the normal support channels on the website and received a reply in minutes. The Foundry support team is attentive and prompt, which is a huge selling point for any software package. It turns out my video card was underpowered for the program, so I transferred to a more powerful machine and the problems were resolved. The

response from support was excellent.Any pro will know that quality support is gold when a deadline is looming and you’re experiencing sudden problems.

Mari strikes me as an elegant, easy-to-use, immensely powerful texturing tool. I came to it concerned that it would be

overly technical and possibly even counter to an artistic approach to painting. That fear was unfounded. I fi nd the paint buffer approach to be a unique and powerful way to work, and the process of baking to the model is nearly invisible to the user if you have the program set to bake on rotate. This package is made to be functional, usable, and powerful.I highly recommend it.

“The animation functionality greatly streamlines the process of evaluating and correcting textures in an animation pipeline”

PROS • Extremely powerful• Easy-to-learn interface• Production-tested

CONS • Requires a powerful PC• Ptex support still forthcoming

Mari is a fantastic texture painting tool. The interface and tools are intuitive, powerful and artist-friendlyA

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Here, the Spline Warper tool is being used to fi t an image stamped into the paint buffer with the Paint Through tool before baking it to the model

You can make changes to all the maps in a scene at once. Here the saturation is being adjusted using a single dialog

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