image map pixellated at distance; crisp up close

#1

I have a model using an image map of sufficient resolution to render crisply when the camera is very close to the object; object fills the screen, image map looks great.

when I have the camera far away from the very same object, that image map looks pixellated!

I did a test clip where the camera zooms in from far away, and the image map looks pixellated at a distance, then gets better and better as the cam gets closer to the object with the image map on it.

I have fiddled with every button and control I could see, and nothing helps this.

Is there some way to make the image map render as crisply as it can no matter where the camera is in relation to it?

the .blend file can be gotten at this link:

problem image map

many thanks,

rc

#2

The further you move the camera away, the fewer the number of pixels you have for your texture to render on. You can’t maintain the save texture reolution as when the texture fills your window. Is that what you are seeing or something else?

#3

No, the aparent texture resolution of an image texture looks worse for distant object.

Easiest way to combat this problem is to render larger than you need and scale down.

#4

when I move the cam back, it looks lousy…earlier in the scene, I don’t recall it rendering that badly…somebody on another forum indicated that there are “many things that can go wrong” with image maps in blender…so far I don’t have specific clues…

I tried turning off mipmap…made no diff…

true there are fewer pixels when you are further away, but what I see is that the pixels appear to get bigger, giving the pixellated appearance.

n

#5

Perhaps rather than turning off mipmapping you could try forcing Full OSA on the Material,
be warned though, it will bring up the rendering time for the material!

Full OSA is found under Render Pipeline in the Links & Pipeline panel/tab in material editor in 2.4x
in 2.5x it’s called ‘Full Oversampling’ in the ‘Options’ tab/section.

#6

personally, I’d choose a different texture. That one has some clipping already happening in it, and isn’t the best quality wise.
I rendered out the animation as you had it in the file, and saw no obvious problems. I didn’t try pulling the camera back any further than it was in the keyframes.
you could also try some depth of focus blur when the texture is in the far background - then it’s not noticed anyway.

#7

I know what you mean about the quality, but don’t know what you mean by it having “some clipping already happening in it.”

what do you mean?

thanks,

n

#8

no, that’s not what I mean. I expect the texture to get smaller, and to see fewer and fewer details as the camera gets further away from the object, just as in real life.

what happens with this file is that, at some distance away from the object, the camera renders that image map with coarse, large pixels.

it’s as though suddenly, it’s rendering that image map as if the image map were 2 dpi.

I’ve never seen this in the other 3D apps I’ve used…but they all have their quirks, to be sure!

n

#9

I’m not sure I see the problem in that file, as you seem to describe it.

A couple of suggestions though - turn off Interpol(ate) as well as MipMap for that texture … and maybe use the Mitch filter instead of Gauss in the Render panel (affects the entire image).

#10

There is absolutely no problem with that texture. No pixelization. Everything works fine. It is just that this texture has two very dominating frequencies and the higher frequency just disapears so the lower is more pronounced. Try using more varied texture with less regular features.

#11

thank you, Yecire…turning off Interpolate is what made the difference.

n

#12

You mean for worse? Without interpolation there will be serious problem in animation - kind of flicker.

#13

well, that’s lousy! thank you for alerting me to that.

I mean that when I un-selected Interpol(ate), the quality of that image map improved to the level I’d expect…

no dang good if it flickers in animation, though.

maybe I should post a render of the kind of pixellation I’m talking about? would that shed light on how to cure what I’m seeing?

n

#14

did you change any of the file’s settings? the pixellation I’m talking about is enough to make you wince…pretty nasty and heinous.

aside from whether that’s the best wood texture, I need to learn what is causing the pixellation I see, and how to cure it.

Most likely, I will end up using a different map, but I don’t want to ignore this problem, which could happen to any map.

n

#15

might help, yes, because I for an example have not downloaded the texture in the first post
(well, my bad I suppose, but yeah…). :-/

#16

I rendered every step in this animation and it is OK. It seems there is pixelisation by the end but that’s only because of the dark pattern on the texture which aligns with pixels in screen space. Turning off interpolation is a very very bad idea. It does the same to textures what for geometry would be rendering without antialiasing. If one needs sharper textures it is better to lower filter size to something like 0.8. And it is software independent. Every renderer does this to textures.

#17

I thank you for your generous act of testing this out on your own time.

why am I seeing the pixillation and not you?

n

#18

Below is a jpg of some comparison rendering I did with this image

the two on the left were done in Blender 2.49b; the top with mipmpa/interpol selected, the one beneath it without.

on the right, the same texture with mipmap on, and set up to 5 render passes of Anti Aliasing; arguably equivalent to the setting I have Blender set to, OSA set to 8. Lightwave goes up to 33 render passes.

as you can see, within Blender, the difference when turning mipmap and interpol(ate) off is huge…very noticeable. For comparison purposes, I rendered the same texture in LW, to show that having mipmap turned on didn’t cause the same pixellation as in Blender.

to me, this experiment shows that there is some setting or other factor causing pixellation in Blender. As I mentioned, all 3D apps have their quirks…Lightwave can produce wonky results, too, but on this, it feels like Blender might be losing track of the actual image map file, and maybe swapping in a preview OF the real file, when the camera is distant to the object having the map.

Is this a possibility?

thank you,

n

map.

#19

I don’t see no pixelation there. The difference is in sharpness/bluriness.
All look OK for me. The differnce may be from the lack in current Blender of more advanced texture filtering techniques which will be in Blender 2.5. The other cause may be in rendering setup. Try other filters with different sizes in render pannel, as your BI renders have quite large blurriness also in geometry (e.g. Mitch, CatRom).

#20

dac77;

thank you…I will experiement with other filters…I have done a little so far, and found that Mitch and CatRom made some improvements.

Just to be clear that we’re using the term in the same way, here’s what I mean by pixellation:

it occurs when a texture or shape are not expressed smoothly, but instead are “chunky,” owing to a lack of sufficient resolution in a raster asset, or failure to properly dither…too few anti-aliasing passes, etc.

the result is that you are aware of a shape or texture being expressed with discreet squares.

Is that how you are using the term?

thanks!

n