Balancing Rendering Quality and Rendering Speed.

A complex, high-resolution image takes time to render. Every 3D designer has to live with this in-escapable truth. But that doesn't mean you have to wait hours every time you want to render an image. Adapt your workflow to include faster, lower-resolution renders at intermediate stages of your design. This is a faster way to fine-tune your settings before you commit to larger, high-resolution render.

Here are a couple strategies for balancing quality and speed in your design process. 

Rendering Quality

When you first create a rendering with IRender nXt, we recommend that you start with a small rendering, 600px width, and just a few passes, start with 20. This will be enough for you to evaluate your lights, shadows, reflections and special effects without spending too much time watching a progress bar. When you are getting the results you want with a 20-pass render, increase the rendering size and add more passes.

Repeat the process until you're rendering at one-half your final size and one-half your final passes. When you're satisfied at this size you're ready to run the final.

Special Effects may require more rendering passes

Blurry reflection, like the lights in the wet concrete in this image, require more rendering passes. So, plan this into your workflow and know that additional time will be needed to evaluate design with special effects. See: Blurry Reflection for an example.

Rendering Quality vs Speed

Rendering quality is largely determined by two things:

• Image resolution - how many pixels wide and tall
• Number of passes - the number of times the rendering engine processes the image

Speed is the inverse of quality. Meaning the bigger the image and more passes you make, the longer it will take to render.

When you increase the rendering width from 640 pixels to 1,280 pixels, it will take 4 times longer to render - because there are 4 times as many pixels. If you double the size again - from 1,280 to 2,560 pixels if will take 4 times longer per pass again.

Similarly, if a 20 pass rendering takes 20 minutes, then a 700 pass rendering will that 700 minutes - or 12 hours. However, the higher the resolution, and the more passes you allow - the better the rendering quality.

Many of our users will use a workflow that includes several intermediatee renders then, they will let the final, high-resolution, high-pass rendering run overnight for the best quality. 

Rendering quality in the IRender nXt trial version

Some people notice the small rendering size, and limited passes which are the default settings for the Trial Version and are concerned that IRender nXt does can not create high quality renderings. This is not the case.

IRender nXt can produce renderings at any size and quality you desire. But to encourage an efficient rendering workflow, we set the defaults low so you can quick feedback on your designs. 

The balancing act. 

Whether your running the IRender nXt trial or rendering images for clients, you'll always be balancing quality and speed as your develop your final designs. But, if you plan a few smaller, intermediate renders into your workflow, you will learn how to create beautiful images in less and less time.

SketchUp Tips

Check out the SketchUp Tips and Tutorials at SketchUp Tips

Use images and textures for faster rendering

Fractal Tree created with RpTreeMaker

SketchUp, and most renderers, do an excellent job rendering images and texture materials.
For background objects, and other objects for which 3D detail is not important, use images instead.
There is a free plugin for SketchUp - RpTreeMaker - which can be used to create tree images which can speed up your rendering time.

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Use Panoramic Views to reveal entire model

SketchUp model by Boothy rendered as a Panorama with IRender nXt and viewed in a web page. You can spin, zoom, look up and look down on the entire scene.

Create a full 360 degree panoramic image which can be turned into a movie and embedded in a web page.

A Panoramic image is created by rotating the camera while rendering to create a full 360 x 360 degree image.

You can create Panoramic Views by check the make Panoramic View check box on the Render Setup Tab dialog.

Most software to process Panoramic Views requires that the aspect ratio be 2:1 (e.g. 2000 x 1000) pixels. So the rendering resolution will automatically be set to a ratio of 2 to 1.

You can view the flash movie made from the Panoramic image here: Panoramic Viewer

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Rendering Tip - Use Lighting Channels for quick lighting adjustments

Lighting Channels isolates the effect of light sources on the final rendering, so that:

• Balance illumination in scene without adjusting individual lights.
• Create dusk and nighttime scene by quickly lowering the intensity of sun and sky.
• Get results faster without having to re-render the scene.
• Quickly adjust the final rendering to get the lighting effects desired.
• Adjust both the sun and sky to create dusk, or nighttime renderings.
• Add 'self glow' to objects - such as TV monitors, or illuminates signs, and adjust them the balance with the rest of the scene.

Balanced lighting using lighting channels.

 

Lighting Channels is an important new feature of IRender nXt which lets you quickly adjust light sources - sun, sky and/or artificial lighting - individually quickly to balance the brightness and light balance of your rendering. (Now: Fully Integrated into the Batch Renderer.)
You can quickly adjust the intensity of each channel with a slide bar and immediately see the effect on the final rendering. This will saves time both in determining the relative intensities to use for light sources and in fine tuning the final image before publication.
While rendering, or after the rendering is completed, you can use the Lighting Channel Wizard to modify the rendered image by changing the intensities of the lighting channels. You can then adjust the intensity of the light sources, or save the Lighting Channel sttings to reuse the same channels in future renderings.

See:  Lighting Channels

Rendering Tip - Use Self Glow for backlit objects

(Self glow applied to television screen)

Self Glow illuminates a surface as if it had light shining on it, without actually making it a light.

* Balance illumination in scene without adding additional lights.
* More realistic signs, monitors and projection devices.
* Faster rendering times.

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Use Procedural bump maps or materials for water

if your renderer has special procedural bump effects they can be used to make realistic water which will reflect buildings, sky and other background objects realistically.

• Distorted reflections to represent water ripples.
• More Realistic highlights from reflection of light.
• Realistic transparency caused by ripples and reflection of light.

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