Texturing questions

A couple of questions for the gurus out there…

1: I have a normal (bump) map of tread on a tyre and it is very noticable that the effect of the map varies with (a) Distance from camera, (b) Resolution of render, © Focal length of camera. This effect is either much less noticable without OSA or doesn’t happen (it’s hard to tell). Am I doing something wrong along the way or is this just the way it is ? It’s a pain in the butt because as I zoom out from the tyre the tread pattern changes from a motorcycle road tyre to something more suitable for mudplugging.

2: I need to add to add text to the sidewall of the tyre (another bump map). Is there an easy way to get the text to run along the sidewall or is it a case of creating text that follows a circle in an external graphics package (Gimp is not good at this) and then playing around with a flat texture map until I get it in the right place and scale ?

3: On a similar note, I want to texture the scratches on a disc brake. I could do this with an image map of noise that has been blurred in a circle but I am wondering if there is some combination of mapping and co-ordinates that will let me do it procedurally.

Setanta

  1. Displacement mapping would probably be better in this case. Map the texture to Disp instead of Nor

  2. Easy to do with the text on curve function.
    Add a text object, modify the text to suite your needs.
    Add a curve circle
    Type the name of the curve circle in the TextOnCurve field of the Text object (Editing window F9)

  3. You could use object mapping (using the Ob mapping mode with the name of another object, most of the time an empty) or use a rather simple UV map. Just map the front of the disk with the From Window option and place it on the texture image with the scratch. Pile all the other faces in a corner of the image where they won’t be affected by the scratch (using a texture with an alpha channel is preferable).

Martin

I’ve done a little experimenting and…

1: Using a displacement map would get rid of the problem, but at the cost of a huge number of extra polys and a major increase in rendering time. Since I can work around the problem easily enough by tweaking the settings and image for still shots, it’s really only a problem if I’m trying to animate something - which means that the long rendering times would be a major problem for me. From messing around a little I reckon that a better solution in my case is going to be rendering oversize without OSA and post-processing the movie (blur and resize). Thanks for the pointer though - I now know a lot more about displacement mapping than i did before :wink:

2: Text on a curve will let me get part of the way there, but unfortunately the sidewall of the tyre is of such a shape that I’d have to do some tricksy deformation of the text mesh afterward to get it to work (it’s basically a circle in the XZ plane, but it is also both angled and curved in the Y direction). Again it would mean a lot of extra rendering time (there’s quite a lot of text on the sidewall of a tyre) so at the moment the method theeth outlined in 3 above seems like a better solution in my case.

3: Yep, this is pretty much what I had figured I’d have to do. I was just interested to see if anyone knew of a way to stretch a procedural texture such as a noise texture in a circle.

Thanks for the input

Setanta

Hi,

about 2). maybe you could go with latices; they rather flexible for those kind of things.

SirVer

Yep, lattices would do the job, but it would still mean a lot of work and extra verts for little gain. Having played around somewhat with things it’s not quite as fiddly as expected to get a bump map to line up so I’ll eventually go with that method. I already have the scratches done that way. My biggest problem now is finding a non-commercial app for mac which will do text on a curve (Gimp does it, but badly)

As to 1: above, I managed to pretty much sort that out by adjusting the ‘filter’ settings for the texture. I wasn’t using mipmapping or interpolation so I had thought from the tooltip that it would have no effect - BOY was I wrong. Changing it down to 0.4 from 1 gives me acceptable results on the tread at different resolutions and makes it easy to tweak if I need to.

Anyhow, here’s a quick render of the state of play at present.

http://www.setanta.nildram.co.uk/FrontWheel.png

Setanta

for 2. I’m thinking use theeth’s suggestion in a different scene or layer and render just the resulting text on a curve. Then use that JPG, PNG or whatever you saved is as, as your texture for the NOR.

It’s astounding…

Yep, that may well be what I do in the end. Either that or give up on my idea of doing this completely in non-commercial software and using FreeHand or Illustrator :wink:

Time is fleeting…

Setanta