REVIEW OF AUTODESK VIZ 4
By Jeff Mottle (jmottle@cgarchitect.com)

Arguably one of the most anticipated rendering and modeling packages to be released this year, Autodesk VIZ 4® (formerly known as 3D Studio VIZ), will just sneak in under the wire as the last full featured Global Illumination renderer to enter the arena in 2001. With a ship date expected to be just before years end, many existing VIZ and Lightscape users will be eagerly awaiting the official announcement and of news that will help them decide if they will upgrade in the new year. Existing VIZ users will be able to upgrade for $495 USD, and existing Lightscape users for $1495 USD. The full retail boxed copy will sell for $1895 USD.

In this, the first product review on CGarchitect.com, we will take a look at a few of the features and additions in this latest release, and hopefully shed some light (pun intended) on the issue.

With the dizzying array of renderers entering the market this year, one has to ask, how there could possibly be room for so many, and how do you choose? The answer may not be so simple. No one package can do it all, and each has its strengths and weaknesses. In the end it will come down to the package that can best meet your feature set and workflow requirements. With this review I hope to make everyone's decision a little bit easier, and although there are too many features to cover in this review alone, I will try to cover most of the major ones, and touch on some of the cool stuff that has been added.

   
  Image courtesy of Guillermo Leal Llaguno - Scream!Point
Click to enlarge		 Image courtesy of Guillermo Leal Llaguno - Scream!Point
Click to enlarge		 Image courtesy of Guillermo Leal Llaguno - Scream!Point
Click to enlarge		  


So where does the Autodesk VIZ 4® fall into this crowded market? Designed primarily to meet the needs of architectural visualization artists, whether that be for interiors, exteriors or office towers and football fields, VIZ 4 had added some pretty impressive features to become a fully featured 3d modeling, rendering and animation application, with a broad range of 3d and multimedia tools. Much of these new improvements and features are direct imports from 3ds max, so many of the big ticket items that you were drooling over in max are now available to you in VIZ 4. That is with the exception of non-architectural related tools like: sub-object animation, video post, particle systems, character animation etc. You do however have access to the new true polygon modeler, subdivision surfaces, quad menus, and Visual Maxscript to name just a few.

Most notable in this release is the addition of a new radiosity technology. "The radiosity engine for VIZ has been completely reformulated", says Stuart Feldman, the Product Manager for AutoDesk VIZ and Lightscape. "The new engine does not use the 'progressive refinement' approach but is based on new statistical sampling techniques that produce fully converged radiosity solutions in a fraction of the time that it would take with Lightscape".
As an alpha and beta tester for this latest release, I will vouch hands down that this is the fastest radiosity processing I have seen. I have been using Lightscape in production for just over five years and there is no question that Lightscape radiosity processing will be left in the dust.

   
  Image courtesy of Guillermo Leal Llaguno - Scream!Point
Click to enlarge		 Image courtesy of Guillermo Leal Llaguno - Scream!Point
Click to enlarge		 Image courtesy of Guillermo Leal Llaguno - Scream!Point
Click to enlarge		  

In addition to the new radiosity technology, Autodesk has implemented a new "pixel regathering" functionality that can be used to calculate the radiosity value of each pixel of a rendered image. So what does this mean to you? If you are or were a Lightscape user, you are probably all too familiar with shadow leaks, artifacting, and having to model specifically for Lightscape. With pixel regathering you will be able to capture all of the subtle shadow details from indirect lighting, that could not be captured in a radiosity mesh, with less artifacting, using normal modeling practices.
But will this new luxury come at a price? You bet! While you may save time up front in the modelling stage, provided you were a Lightscape user, you can pay big time in render times and RAM consumption if you are not careful. Make no bones about it, if you choose to regather an entire scene, VIZ4 will eat up as much juice and power as you can throw at it, and in full res production renders, regathering will most likely not even be an option.

So how can you tell how well your scene will do VIZ 4? It will be pretty hard to determine. Depending upon how much of your scene gets regathered, the resolution of your image, types of materials you use, and the number of lights in your scene, render times can vary from minutes to days. Although, the addition of an improved network renderer and multithreading will help alleviate some of this.

So with that let's dive into the interface and new features.

   
  Image courtesy of Guillermo Leal Llaguno - Scream!Point
Click to enlarge
Autodesk VIZ 4® screenshot
 Image courtesy of Guillermo Leal Llaguno - Scream!Point
Click to enlarge		  


NEW FEATURES AND INTERFACE

RADIOSITY INTERFACE

Although there are many new features in the this release, the new radiosity technology will be the most talked about, so we'll start there first. Probably one of the simpler user interfaces for a radiosity renderer, Autodesk had taken most of the guesswork out of the initial setup. Although you do need somewhat of an understanding of what the technology is doing and how radiosity works, most users should find it relatively easy to set up their scenes with a bit of experimentation. Like any program, you are not going to be able to just press render and miraculously get the next Mona Lisa.


As you can see there are relatively few options to set in the radiosity dialog. The initial Quality spinner allows you to set how far to process the solution. This will determine how physically correct the lighting in your scene will be. Similar to Lightscape's iterations.
Refine iterations and filtering allow you to improve image quality by reducing noise and lighting variation in your scene. You also have the ability to refine only certain objects in you scene. This can be useful to correct problem areas, and can reduce render times by not having to refine large areas. It is with these tools that you can tweak your scene to achieve relatively good results, without having to regather.


The meshing parameters dialog allows you to set how the geometry in your scene will mesh at render time. Very similar to Lightscape's mesh parameters, but on a global basis and not adaptive. As VIZ calculates the lighting from discreet points on the mesh, more dense meshing will produce more accurate lighting. However a dense mesh will result in more RAM usage and longer render times. As with refine iterations you also have the ability to override the global meshing and produce more or less dense meshing on individual objects in your scene.


Even after refine iterations and filtering you may still have the odd artifact in your scene. With the addition of the light painting tool, you can touch up any trouble spots by painting on the mesh to add or remove illumination.


The second to last rollout in the radiosity dialog allows you to select how you will be calculating the lighting in your scene. It is here that you would enable regathering. The first option "Re-Use Direct illumination" will not re-render your direct illumination, but rather re-use the direct lighting that was stored on the radiosity mesh during the radiosity processing. Quality will be dependent upon the mesh resolution you initially set. This setting can be useful for animations as the direct lighting does not need to be recalculated for each frame.
The default rendering mode "Render Direct Illumination" uses the VIZ scanline renderer to calculate each light's direct illumination, and then applies the indirect illumination, that was calculated during the initial radiosity process.
   
  Image courtesy of Lon Grohs - Neoscape (VIZ Regathering)
Click to enlarge		 Image courtesy of Lon Grohs - Neoscape
Click to enlarge		 Image courtesy of Lon Grohs - Neoscape (No Exposure Control)
Click to enlarge		  
   
  Image courtesy of Lon Grohs - Neoscape
Click to enlarge		 Image courtesy of Lon Grohs - Neoscape
Click to enlarge		 Image courtesy of Gary Rackliff
- R. Miller Visualization
Click to enlarge		  

Now for the option that everyone has been hearing so much about - Regathering. Used in conjunction with render indirect illumination, regathering will recalculate, on a pixel basis, all of the indirect illumination in your scene. With this option you will get the most impressive results and the most accurate and artifact free images. However, as I have mentioned earlier, you will pay for this level of quality in both RAM consumption and CPU power, and of course very long render times. To help speed up these times, you have a few options to help you out. In addition to being able to selectively choose which objects in your scene will be regathered, you also have the option of adjusting the number of rays per sample and the filter radius to achieve a balance between and image that is too grainy and and image that looks good and doesn't take too long to render.


The last rollout, as the name suggests, relays all of the statistics for your scene and radiosity processing.

For those of you who will be using VIZ to render out animations and walkthroughs, you will be glad to hear that animated objects are now an option with radiosity, however this will require you to recalculate the radiosity for each frame.




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