View Full Version : Dumn Question!!

04 April 2002, 05:07 PM
I know this is dumn but...

Does upping the dpi value of a texture within Photoshop (.tga) enhance the surface rendering within Lightwave in any substanial manner. If so is there some sort of tradeoff with rendering times.

I only ask as I have seen textures to die for and wondered how to achive that level of detail in a texture when rendering from LWS at a large output size.


05 May 2002, 06:05 PM
short answer is no...Starting out with a texture at the right dpi is critical. using low rez images will result in the same look when you render. if you increase the dpi in photoshop (which you should not ever do!) does not magically make a low rez image into a image that can be printed in a art book! photoshop will just interpolate the pixels and the result is a blurring image.

instead of increasing the dpi in PS turn on supersampling in LW...

Iain McFadzen
05 May 2002, 06:32 PM
DPI is completely meaningless in digital media, it stands for Dots Per Inch, and tells a printer how many pixels (dots) of image data to sqeeze into every inch of print. A 300*300 pixel image at 72dpi has exactly the same number of pixels as a 300*300 pixel image at 900dpi, and will be treated exactly the same way by your 3D app.

05 May 2002, 07:51 PM
So let me get this straight.

If I use an image 500px by 500px instead of an image of 150px by 150px the qualty of the texture will improve i.e. scaling it down to fit the same poly area as the smaller pic.

Should I still turn on oversampling though.

Thanx for your comments so far though. Nice to see people interacting in this place to a newb with limited talent.

05 May 2002, 02:50 AM
You should make your texture size according to your output resolution, and how much of the screen the surface covers when it's as close as it's going to get. In other words, if you are doing an animation, and you have a wall that you pan past that takes up at most 300x300 pixels on screen, then make that texture at, say, 320x320. You don't want to make the texture too small, but you also don't want to make it too big. Textures that are too small look pixelated and textures that are too big look like they are sparkling. Mipmapping handles the case when they are too big pretty well by making a smaller version of the texture and filtering it, but when the texture is too small, it makes the texture bigger and when it filters it, it gets blurred which makes it looks out of focus, which would ruin any DOF effects for instance. Anyway, what I'm getting at is try to make the textures about the same size as the surface they are assigned to takes up on screen.

05 May 2002, 01:59 AM
They are right, forget the dpi, for 3d only the pixel size of an image matters.

Should I still turn on oversampling though.

Oversampling (called supersampling in some packages) is to counter 'flickering' of very detailed textures. Sometimes you have a material that has a lot of small details, which tend to flicker when animated.
The renderer samples the texture, but because it has so much detail it samples very different values every frame.

Oversampling tells the renderer to take multiple samples of the texture every frame, and averages the samples to one value which end up used as the pixel you see on screen.

So the oversampling option doesn't necessarily make your texture look better, and because it gulps up a lot of CPU time, you better leave it of unless needed.
Sometimes I also use oversampling on textures that contain text, I had times where the text wasn't readable enough and turning on oversampling made it look better.

Another tip for textures is to use grayscale images for bumpmaps, (and any other map that doesn't need color) it's only a third of the memory of an RGB image.



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