System Requirements

Bob — Tue, 25 Sep 2007 16:56:00 GMT

Supported Products

AutoCAD 2007 or 2008
Revit 2007 or 2008
Rhino 4.0

Windows XP or Vista

Vista requires administrator rights for installation

AR4 is needed for now to do anything useful. Later we will remove this requirement.
Note: The AR4 eval will work. The libraries are limited.

Getting Started

admin — Mon, 24 Sep 2007 16:54:00 GMT

This is a pretty early prototype of a new rendering engine that I've been experimenting with. There should be enough here for people to at least take a look at. Please be in a friendly mood when trying this stuff, it is still early. That being said, I do welcome any and all comments, and although I may not agree with everything said, I will listen carefully. I am still not sure whether this stuff belongs in an AccuRender 5 type product or whether this is something entirely new. It is very different and it may be time to nuke some of the old stuff.

Basics

To load the new engine for the first time in an AutoCAD version:

Appload the file "accurender nXt.arx " in 32-bit Operating system -OR- "accurender nXt 64.arx " in 64-bit Operating system. You can also drag and drop one of the files from explorer onto an open AutoCAD session. You only need to do this once-it will demand load after that.

To run the new engine type: "ar5".

This brings up a very rudimentary control panel interface which is the working prototype. It also displays an AccuRender palette which will contain the new interface-this is not working yet-you cannot render using this interface, but you can still play with it and tell me what you think

On the right side of the control panel are four "Presets"-Industrial Design, Exterior, Interior Daylight, and Interior Artificial Light. The easiest thing to do when you're first getting started is to choose the most appropriate one of these and let it handle the settings below. An "Interior Daylight" rendering is probably the most adventurous of these settings-you may want to wait a few rounds and read the section below before trying one of these.

Start a rendering by selecting Render->Render from the pulldown. Currently, only 640 x 480 resolution is available. Renderings no longer stop automatically; the process will continue to refine the image (forever) until you tell it to stop. Stop the rendering by hitting the Esc key or use Render->Stop. You can let a rendering continue for seconds, minutes, hours, overnight, or for a week-it's up to you. Some renderings won't change much after the first few seconds. Many images though, particularly those with things like soft-shadowing, blurry reflections, interior daylighting, will continue to improve. Some rendering will require a long time to converge on an adequate solution.

I will, of course, be adding some automatic stopping criteria for batch type work like animations. These will probably, at least initially, be simple criteria like time or number of passes. I will also add some paranoid automatic saves for long renderings.

Renderings can be saved to .jpg format or .tif (tiff files have an alpha mask) using Render->Save Rendering.

Performance Notes

A. The basic engine should be at least 4-5 times faster than the old stuff under most conditions. It's going to be very difficult to compare the render speed to AccuRender versions. The closest you can get in terms of render settings is to use the Exterior preset and uncheck the box marked Sky Light. This is similar to the old illumination algorithm. A pass or two should yield similar or better anti-aliasing characteristics.

B. The status bar will display some important information during a rendering. It should look something like this:

Pass 29(416) 00:01:59 1137611 104006

The pass count is incremented each time the renderer makes a pass over the entire rendering. Each pass provides 4 samples per pixel.

I'm pretty sure the number in parentheses represents the last completed scanline of the pass.

The clock shows the elapsed time in hh:mm:ss.

The next number represents rays/second and the final figure is pixels/second. These two are very important performance metrics. The second, in particular, will tell us how long each pass will require.

C. The performance of the engine should no longer be impacted as much by having a small detailed model on a large site (the teapot in the stadium phenomenon). An exception to this is indirect lighting from sky and sunlight; it's better to have smaller models if you need this.

D. The performance of indirect lighting will not be impacted very much by having a lot of faces to render. This is a large improvement over radiosity, which is sensitive to model complexity.

E. The thread scheduler has been redone and should be much more efficient on machines with 4 or more processors.

Notes on Interior Daylighting

Daylight sources are an option, not a requirement, for interior sky light. Using daylight sources will make the images converge much faster. Interior daylighting works pretty well without them for single rooms or small models on small sites with relatively large windows. These models will still benefit from the faster convergence of daylight sources

If you attempt to render an interior daylight simulation of a small room in a large model without daylighting sources you will probably be disappointed. Daylight sources should help a lot in this case-but try it if you've got the stomach for it and let me know how it goes.

If you model glass with a single sheet you'll get more realistic refraction if you tag the object as Thin using Ar4/3.

Notes on Skylight (hdr)

Sky light is provided using either an analytical sky model or an hdr Image file. Controls for this are under Sky Type. You can select an hdr file using the button to the right of the Image checkbox. I don't think there's any way at the moment to change the direction of (rotate) the hdr sky. I'll get to it soon.

Material Editor Prototype

Under the Test pulldown is a prototype of an interactive material editor using hdr lighting for the preview. You can save/load materials to/from individual files. There is also a concept of template materials which present simplified versions of the material editor. You cannot assign the new materials to objects in the drawing yet, this is coming soon. Some of you may notice that there is an anisotropy setting-it doesn't work well yet.

Coming soon (partial list, I'm sure I've forgotten lots of stuff)

Saving the new settings (presets, etc.) to the drawing
Resolutions other than 640 x 480
Rotation of hdr sky light
Assigning the new materials
Infinite ground plane
Many plant settings
Bump mapping
Decals
Waves

Not sure if I'm going to implement yet

WalkAbout-may implement some navigation tools to supplement AutoCAD's-but it may be time to kill our own OpenGL viewer.

Unlikely to be implemented

Radiosity-too many problems, too many artifacts, too many restrictions, too much knowledge required by users-I think we can do better for most users. Some people will definitely miss this.

NXT for AutoCAD First time...

admin — Mon, 24 Sep 2007 16:34:00 GMT

To load the new engine for the first time:

Appload the file "accurender nXt.arx ", or drag and drop it from explorer onto an open AutoCAD session. You only need to do this once-it will demand load after that.
To run the new engine type: "ar5".

After getting AccuRender up and running, you may want to visit Getting Started for a closer look at the interface and workflow of nXt.

Manuals nXt for AutoCAD

Textures

System Requirements

Getting Started

NXT for AutoCAD First time...