Producing "depth of field" effects??

[propstuff]

Hello all,

Since I got RW, with practice, I've been using it with some success to do proposal presentations to customers.

Numerous people have asked if the renderings were photos. Thankyou to Dave D, Biplab etc etc etc.

Now; despite reflections, shadows, transparency etc, my renderings dont *really* look like photos of the finished

thing because photos of furniture almost always have limited depth of field. So..............

Any ideas how to produce this out-of-focus effect??

cheers,

N.

[Peter van der Elst]

Photoshop could be a good tool to blur foreground (like furniture) and background objects.

[propstuff]

Actually peter, given that my business *is* Furnture, I'd rather like to keep that IN focus. :-D

Photoshops Blur tools are good but I don't know of a way to make it progressive with distance. Perhaps using a gradient as a Mask or somesuch??

The way I have been presenting designs is to make a "stage" from the corner of 2 walls, with a window spilling light, and a carpet or timber floor. Then I plonk the piece in that and light it.

It's fairly effective, except for the uniform focus......

Would such a tool be useful for architectural renderings?

[Dave Donley]

Hello propstuff:

RenderWorks doesn't provide depth of field.

Thinking about this and since you have Photoshop, maybe you could try something crazy like rendering multiple images with very slightly different perspective values then add them equally together in PS to make a single image with blurry far edges.

This is essentially what is done by the Monte Carlo ray tracing method - rays originate from random places on the camera lense and they are all blurred together. All rays pass through the focal point. Rays originating on the far edge of the lense would have a wider cone angle than ones that pass through the center of the lens.

The perspective would have to change by very little amounts, to keep the near parts of your model more in focus.

You could do this by defining a batch job, shifting the perspective value, and defining another batch job. Then render all the jobs in one go. I would think you would need about 6..8 frames to blend together.

p.s. This is similar to something I suggested to get soft shadows with ray tracing of transparent shadows - create multiple jittered directional lights to approximate the area subtended by the sun's disk.

HTH,

[ 12-01-2003, 05:01 PM: Message edited by: Dave Donley ]

[propstuff]

hello again Dave,

I got some advice on using PS, and did some experimenting.

From PS6, it *is* possible to make a mask and apply a gradient to it, then turn the mask into a selection, and apply blur to the selection.

This produces a proggressively blurred image.

The effect on my "3/4" view settings is reasonable but being a 2D effect applied to a 2D rendering there are inevitable unrealistic anomalies. I think that for architectural renderings most views would not work well.

Your proposed method sounds interesting, but given the 20-30 mins it takes to get just 1 finish rendering out, I'm going to need a fair whack of spare time to try it out. Not in the near future :-(

When you said RW does not do depth of field; did you mean that it's not capable of it, or that it's possible but difficult (read expensive) to implement; or perhaps possible but there's not sufficient demand??

BTW, I had a go at your skydome for lighting the furniture, but not very effective. No surprise there really given that it is intended to emulate the sun. It was worth a shot though:-)

cheers, N.

[Dave Donley]

Hello (Saint?) Nick:

quote:

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When you said RW does not do depth of field; did you mean that it's not capable of it, or that it's possible but difficult (read expensive) to implement; or perhaps possible but there's not sufficient demand??

BTW, I had a go at your skydome for lighting the furniture, but not very effective. No surprise there really given that it is intended to emulate the sun. It was worth a shot though:-)

---

Depth of field is an option with the Special Effects module from LightWorks, which we don't license for RenderWorks. Here's a quote from the LightWorks web page:

"Provides a range of visual and special effects for adding increased realism to images, including lens flares, physically accurate depth-of-field, halation and glare calculations. Incorporates animation capable rendering to give the highest quality of output for recording and displaying on video, including field rendering, video filtering and motion blur."

Send me a file of one of your furniture pieces and I'll try rendering it with a skydome; I'm curious.

[propstuff]

quote:

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"Provides a range of visual and special effects for adding increased realism to images, including lens flares, physically accurate depth-of-field, halation and glare calculations. Incorporates animation capable rendering to give the highest quality of output for recording and displaying on video, including field rendering, video filtering and motion blur."

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Well, for goodness sakes Dave; why did you tell me THAT! Now I want it ALL!! :-O

[actually I can live without the video stuff ;-) but the rest:........... RW11? ..........yes?........ PLEEEEASE? ]

The results I got with your skydome were a constellation of little pointy angled shadows. Not very "real". Perhaps the dome was too close to the object??

I'll see what I can do about compressing a file to send you.

cheers

N.