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AndyBard

getting render whites, whiter than grey

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I use white walls a lot in my gardens and I mainly use cartoon artsitic renderworks.

I realise that a white render needs a colour associated to it, i.e the standard grey, but is there a way of lightening the grey colour so it looks whiter without having to mess about lights.

Thanks

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Guest

Using Artistic RW, getting a pure white wall is difficult. Even in RenderWorks rendering modes, white walls still come out gray. Radiosity gives the most realistic color display, especially with whites.

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would it better to increase the background light levels or play around with a sun position

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This is a constant problem -specially for interiors. :-(

Increasing the Ambient will help, but you'll have to juggle the other lighting to compensate.

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.. and use radiosity in the final rendering.

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.. and use radiosity in the final rendering.

Yes it's true that Radiosity gives more accurate results Katie, but that's not really an "answer" to the problem.

In my experience....

Getting a Radiosity set up well is not really any quicker than setting up a conventional render well. Unfortunately the inherrant slowness of Radiosity means that every tweak of the lighting or the Radiosity settings takes much much longer to try out.

Furthermore, just as the results from OpenGL rendering bear little or no relationship to the results for Final rendering (with the same lighting set-up); the other faster render modes can't be used to set the lighting for a Final Radiosity render. Even an optimised Fast Radiosity render can take 1/2 an hour to get a result which might need adjusting again and again.

Frequently the time impost of Radiosity is just not appropriate.

The problem remains that White does not render as White, but something else instead.

I don't know whether this is a problem with the rendering engine itself, it's implementation in RW, or rendering solutions generally, however; it's been a constant problem for along time. Where time is not important Radiosity might help, but it would be better if it were possible to correct the problem "at it's source" and have the quicker rendering modes display something closer to reality.

regards,

N.

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Hmm.

Even a white surface is pitch-black if there is no light present. So perhaps the problem is inherent to the laws of physic, that Renderworks mimicks. In my old Studiopro, however, there was a neat solution to this, that should be very easy to include into RW: Glow. Any texture in Studiopro can be set to glow a certain percentage, which means, that it renders lighter than what the lighting of the scene dictates. It is like Renderworks 'Constant' reflectivity, but it is incremental.

That said, there are tricks to get around the problem in RW today.

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'another solution is set up multiple light sources very near the object and shining on it to lighten only that area.'

This is render-heavy, though.

Here is a simple trick, that I have just recently discovered the full potential of:

http://homepage.mac.com/kaarebaekgaard/.Pictures/Test_glow.JPG

Notice that one wall is evenly grey - but the other has a varying whiteness. No lighting is involved except the global lighting of the scene: An imageprop has been placed slightly in front of the wall. The image is all white. The settings are: Disable Lock Aspect Ratio - Use Mask/Create Mask/Import Image (use a gradient image as shown below)/Source for Mask: Greyscale Pixels - Click OK and disable Crossed Planes - enable Constant Reflectivity - enable Create Plug-in Object (enables you to scale imageprop freely) - disable Auto Rotate to Viewer - enable Create Symbol

Here is the colour file - If you want a warm glow, make it slightly orange.

http://homepage.mac.com/kaarebaekgaard/.Pictures/glowcolour.jpg

Here is the mask file. The whiter areas will glow, the darker will be transparent and allow any texture of the wall to be seen.

http://homepage.mac.com/kaarebaekgaard/.Pictures/glowmask.jpg

The imageprop has become part of the symbol folder and can be scaled and reused for all walls on an individual basis. This effect can actually emulate radiosity to some degree - but it is lightening-fast to render.

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I think the easiest way to get white instead of gray is to use a texture that has constant reflectivity shader with white color. This would render as pure white.

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The problem traditionally has been that any white 3-D object

often renders as grey, and appears excessively dark (I think it

actually renders accurately, it's only a perception issue I believe).

Adding and adjusting lights is too time-consuming and often yields

unexpected results (and increased rendering times). There's no texture

combination (meaning with reflectivity, etc.), to my knowledge, that

can lighten the appearance of such a 3-D object in a controlled fashion

other than Constant, as Biplap suggests, and that one is uniformly white with little ability to accept subtle shadows. After some experimenting, I think

there's a way to do this, and thought I'd post it here for those who

are working with radiosity.

For a ceiling: make an extruded 3-D object with a white fill. Duplicate

it in place, and nudge the duplicate down by a couple of pixels, just

enough to see in close-up wireframe. Create a Constant texture, and

give it about 80% transparency. Apply this texture to the nudged

duplicate 3-D object. The transparency of the Constant texture will

allow the underlying object to be seen as a solid, but the 20% texture

visibility will create a lighter appearance, while allowing subtle

shade and shadow effects upon its surface.

An example of such a texture can be seen here:

http://www.danjansenson.com/whiteceiling/

Note that the ceiling above and the wall to the right both have white

fills. It's only the ceiling duplicate that received the 80%

transparent Constant shader. The white-ness of the ceiling can be

controlled by altering the amount of transparency in the texture.

Dan Jansenson

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I do a lot of interior rendering in formZ which uses the same underlying rendering engine as VectorWorks.

I've found that the best lighting scheme for interiors is to use linear lights. You may have to crank up the output further than logic would dictate.

This image was done using the lightworks raytracing engine:

http://www.threedt.com/projects/proj_qbg_1.html

For a pretty complete discussion of this you could take a look at the formz forum. This is the link to this topic. You'll have to wade through a bit of discussion that's a little specific to formz but about 2/3rds of the way down it gets a little more general

http://www.formz.com/forum2/messages/16/13407.html

The idea of cranking up the ambient light or adding a heavy dose of constant reflection to the ceiling will not ultimately give you the effect you're looking for. To go back to the original question, once the whites are reading properly in properly in the raytraced rendering they should work out ok in artistic modes as well.

Rick

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