folded or crumpled textile

[Anonymous]

Hello
How can I make in 3D a folded textile, and a crumpled textile ?

Thanks for your help!


Charlotte C.
student in architecture

[Aussie John]

Sorry Karl Iwas meaning in photoshop. If you take picture I dont know how you make the image align on opposing sides so they will flow seamlessly when joined to form a texture

[Dwight]

Building a seamless texture from a photo involves copying pixels for uniformity.

If you are on mac, a utility called "Texture Magic" will assoist you in copying pixels and provided a full-screen preview to show the repeat pattern.

In photoshop, you can copy pixels across image edges by using the offset - locate - see attached

[Dwight]

and here it is

[Karl Ottenstein]

Aussie wrote:
Sorry Karl Iwas meaning in photoshop. If you take picture I dont know how you make the image align on opposing sides so they will flow seamlessly when joined to form a texture

Figured I misunderstood! 😉

Thanks to Dwight for providing the answer. Let me add a couple of other comments since this thread was started by a student for whom these things may be new concepts.

When a "seamless" texture is repeated, you should be unable to detect where the edges of the original image lie. Even in the case of a single tile with grout repeating to show an entire surface of tile, the edges need to be managed as Dwight desribes to avoid an observable pixel line when the image is repeated.

But, a "seamless" texture does not mean that it lacks a repeating pattern - desired or undesired. An example of an undesired repeating pattern is the grass texture in the standard ArchiCAD materials which is seamless, but which has an unattractive repeat.

The wallpaper example is one where the pattern of the paper should repeat, but the edges of the base pattern should not be visible ... and so again, Dwight's technique is used to shift the pattern (offset filter) to clean up any edge pixels if required.

Back to textiles!

Fabric can be deformed, making the creation of a seamless, tile-able texture a little challenging. Camera lenses cause other issues. (A scanner eliminates the camera lens issue - but as mentioned in my earlier post, it does not give a genuine sense of the appearance of the fibers.)

Before taking a photo of a textile, is should be blocked to be as perfectly rectilinear as possible. If you manage to do this perfectly, then lens distortion is the main thing to address in making a texture.

Avoid a wide angle lens. If you use one, then use the free Panorama Tools plug-in for Photoshop to remove the lens distortion.

If the image is taken at a slight angle to the fabric / textile, then when you use offset, the rows (weft, knit, whatever) will not align since they will be denser on one side of the image and spaced further apart on the other side. Use the Photoshop Transform/Distort command along with the Photoshop Grid (ctrl-') to make the rows and columns (warp and weft) of the fabric rectilinear. Then try the Offset filter again. Repeat as necessary.

Below is a screenshot, with contrast articificially adjusted to help make the pattern show. The red grid is the Photoshop grid (you can change the color and size). The red arrows show that at the top, there is only a slight shift from the left to the right of the image, but at th bottom, there is a greater shift. The Distort command will correct this "bias"/distortion. (I just took a quick photo without blocking, and intentionally holding the camera at an angle to the surface. Bad lighting, etc. just because I'm doing this as I type.

Karl

[Karl Ottenstein]

After free-transforming the image to make the rows and columns align reasonably (not perfect because there is some distortion in the fabric since I did not block it), I cropped one repeat-pattern and used the Offset command as indicated by Dwight.

This results in the image attached. The red arrows show where the "seams" are - the original edges of the cropped image before the offset.

You can see that the vertical edge matches surprisingly well and does not need much touch-up. The horizontal edge has a noticeable pixel pattern and requires some cloning after trimming another pixel row or two off.

Karl

[Dwight]

Copying edge pixels often enhances another problem - illumination is not totally uniform so the repeated image "pulses" once tiled.

The user must be very careful to also copy enough pixels into the main body of the sample to disguise this problem.

Of course, experimenting with the procedural shaders of LightWorks, coupled with bitmap masks for tile edges can help overcome this problem by eliminating the need for phototextures in most cases.

And yes, that is gorpy granite. This project is, after all, art for a Haitian Bordello.

[Karl Ottenstein]

Again, for our student, here is the result of creating an ArchiCAD material using the resulting texture image and applying it to the "Sofa 03" library part.

You can see a few issues with the result. The image repeats seamlessly, but there is a stripe (pointed out with arrows) that is darker than the rest of the fabric ... this is because I didn't take the photo in a location with even lighting. [Edit: see Dwight's post on 'pulsing'... posted while I was typing this! Thanks Dwight!]

Within that dark stripe, you can see a repeating little dark "glob" ... something that could have been fixed in Photoshop.

The most unsatisfactory problem is the way the fabric wraps onto the arm of the sofa. You'll see that the pattern on the top of the back and top of the arm all aligns, but the side of the arm is offset. This is an issue with the actual GDL library part and cannot be fixed without GDL coding. A similar thing happens in the curved part of the back, the stripes align, but the pattern is shifted up. No user control over this.

Karl

[Anonymous]

Now all I have to do is have ago myself, one of these days.

Julia

[Aussie John]

yep all these things take time and there always is a hiccup along the way to make it take a lot longer than you hoped. Once it is done though it then becomes a time saver or gets the result you want. I have to confess to spending way too long get some library parts to work but in the long run has been worth it