Texturing & Scaling For Uploading

[jaq Seriman]

I use Photoshop and Illustrator to texture for SL. I've been using textures to paint cars in SL. I've done this before with good success. I'm working with a car now where I've placed a painting grid on each face of the car then placed the same grid in Illustrator (it handles text much better and crisper than Photoshop). I've made the page in Illustrator the same size as the grid (actually I've tried several sizes from 1024x1024 down to 256x256. I place some text on the grid exactly where it falls on the car in SL. When I bring the test texture into SL it does not fit the car. I have to resize the texture on the car to make it appear on the car and when I do this it makes the text look lower resolution. I've tried exporting the image as a PNG at 72 dpi, 150 dpi and 300 dpi. The higher the resolution the crisper the text but sometimes I get a message that I cannot import higher than 1024x1024. Since the original page in Illustrator is not larger than this the only thing I can figure is the resolution is too high. So I lower the export resolution and it will upload but again it lowers the resolution of the image. 

I've tried about everything I can think of, even uploading the texture as the same grid as I've placed on the car in SL which looks like it is in the same position. This is becoming very frustrating as I've had great success before using mainly Photoshop. And I know some cars created for SL have the faces tortured so badly you can't really do much graphics wise to "paint" the car. Short of just placing the text and graphic and rescaling and repositioning it once on the car I'm about out of ideas. I'd much rather place a graphic and upload the texture and place on the car. I hate spending hours working on textures then not having them come out looking good on the cars. 

I've attached two images of the same car I did recently in Photoshop. It looks good but Illustrator just handles text better and the car I'm doing now will have a lot more text than graphics. Any suggestions are welcomed. Thanks.

[ChinRey]

11 hours ago, jaq Seriman said:

The higher the resolution the crisper the text but sometimes I get a message that I cannot import higher than 1024x1024.

I'm not sure I understand exactly what the problem is but this is definitely not correct. The largest size you can upload is 2048x2048. You won't get that resolution in SL, the uploader will scale it down, but it should be accepted and generally the uploader tend to do a better job scaling down images that Photoshop or Illustrator.

If the texture is less than 1024x1024 - even by as little as a single pixel - it will be scaled down to 512x512.

Edited December 13, 2020 by ChinRey
Better formatting

[arton Rotaru]

DPI is for printing. On screen we just deal with pixels. There are only so many pixels in a 1024 x 1024 texture. You can't have more than this, no matter what you try. It won't be more than 1048576 pixels.

Depending on how the car is UV mapped, and it's materials are set up, there might be much less space on a texture sheet, for certain parts of an object, than 1024 by 1024 pixels.

[jaq Seriman]

15 minutes ago, arton Rotaru said:

DPI is for printing. On screen we just deal with pixels. There are only so many pixels in a 1024 x 1024 texture. You can't have more than this, no matter what you try. It won't be more than 1048576 pixels.

Depending on how the car is UV mapped, and it's materials are set up, there might be much less space on a texture sheet, for certain parts of an object, than 1024 by 1024 pixels.

Being a printer I've dealt with DPI for years. My experiments with uploading textures shows that when I export an image from Photoshop at 300 DPI the resulting upload looks much better or sharper than if I export that same image at 72 DPI. The sad part is most content creators or the people that create the cars in Blender or whatever 3D program of choice, do not create the UV Maps for those cars. This means we must use painting grids for positioning. As I stated it seems using this grid system is not infallible as my uploaded image is not fitting the face of the car as should be the case. That's why I asked the question if resolution would affect the image upon uploading to the viewer. 

I've uploaded many many textures into SL and sometimes I have to resize the image once placed but this one seems to be a bit different. I just want to find that magic formula where I can create a texture in either Photoshop or Illustrator and get consistent results. Especially with text as Photoshops raster imaging tends to cause blurry text. I may be older but I still embrace learning something new.

[arton Rotaru]

Yeah well, unfortunately there is no magic wand for this. If the UVs are distorted in one way or another, you will always have a hard time putting anything accurate like text there.
Also when the portion of the model is only a small section of the texture sheet. Since the max texture size in SL is 1k, but, lets say a fender is just mapped into a corner of that 1k map, there will be only like 300 X 200 pixels for the fender.

A method to deal with distorted UVs to some degree, is by projecting a graphic onto it. But this would require a 3D painting program, and the actual model to be imported into that indeed.

[Quarrel Kukulcan]

2 hours ago, jaq Seriman said:

Being a printer I've dealt with DPI for years. My experiments with uploading textures shows that when I export an image from Photoshop at 300 DPI the resulting upload looks much better or sharper than if I export that same image at 72 DPI.

PNG files don't include DPI information. They don't know inches -- they only store the dots. And 512 dots is 512 dots is 512 dots, regardless of whether those dots are intended to be displayed at 96 DPI on a monitor or printed at 300 DPI on paper.

Notice something, though: those 512 dots cover 5.33" on the screen but only 1.71" on paper. If you want to print enough dots on paper at 300 DPI to cover the same 5.33" distance they take on your screen, you need 1,600 dots. And that's what a vector-based drawing program like Illustrator or Inkscape (or even Photoshop, if it has non-rasterized text or vector objects) do when you tell them to export at higher DPI: they redraw your image internally, from scratch, at a higher base resolution than your screen shows, then export that.

That is EXACTLY what you want to happen if you're creating images to be printed at 300 or 600 or 1,200 DPI. You get all the extra dots you need to cover the same real-world distance on your flyer or backdrop or poster as on your monitor, and you get them by redrawing all your text and other objects at a finer detail level in the first place (which looks good!) instead of by taking the drawn-on-screen image and upscaling it into a blocky, low-res mess (which looks bad).

But you don't want that for 3D texture work. If you make a 512 dot image because you want a 512 dot image, but you export at 300 DPI, you'll get a 1,600 dot image (which will be a lot crisper because there's so many more dots), which Second Life will shrink back down to 1,024 dots (which will STILL look crisper, just not as much). If you export it at 600 DPI you'll get a 3,200 dot image that's too big to upload.

Edited December 13, 2020 by Quarrel Kukulcan

[Whirly Fizzle]

Also have a read of this excellent blog post by Beq Janus which explains how to get your uploaded textures looking as crisp as possible.

http://beqsother.blogspot.com/2019/02/compression-depression-tales-of.html

[jaq Seriman]

Here is a simple test I did on an object sent to me by a reader of this forum. I took the maps given and placed a simple color box on all four corners of the object. Then I exported this (from Illustrator) as a 72 DPI PNG file. As you can see when I placed this texture the drivers side red panel fits perfectly but the others are all well off with only the rear panel showing near the bottom of the passenger side rear fender and the panel on the nose of the car barely visible near the bottom edge. This puzzles me. I've had some textures where upon placing were a bit off but nothing like I'm experiencing now. Thank you to our forum reader for your object to test.

[Aquila Kytori]

I have just repeated your test using Gimp:

 

and as expected the blue test marks are perfectly mapped to the model.

Can you confirm that the Image exported from Illustrator is exactly 1024 x 1024 pixels ?

And also that when you double click on the texture in your inventory to open it that it indicates the same 1024 x 1024 and that the scale ratio is 1:1 as in the image below :

 

Note that there is also a little red spot on the very front, left in your first screenshot and the red mark on the side panel seems a little blured top edge.

 

 

Edited December 13, 2020 by Aquila Kytori

[Quarrel Kukulcan]

Okay! There's the misalignment problem. The car was UV unwrapped to the bottom regions of a square texture, but the OP appears to be uploading a rectangular one trimmed to just the car area. Look where the markings on the red-blocked texture end up once the coordinates align.

When you make a texture for an object, you have to match the proportions it was originally UV unwrapped onto. (You CAN change the size, but not the aspect ratio.)

 

Edited December 13, 2020 by Quarrel Kukulcan

[Aquila Kytori]

I have just did a test with a cropped image, 630 x 1024px size when exported from gimp and reduced again to 1024 x 512 as expected when Uploaded to SL.

 

and when this is applied to the model it looks remarkably similar to yours:

 

 

Somewhere along the line the texture is being resized. probably when exporting from Illustrator .

 

 

@Quarrel Kukulcan  Yes I think we are in agreement the texture is being resized somwhere.

Edited December 13, 2020 by Aquila Kytori

[Quarrel Kukulcan]

(bad info)

Edited December 13, 2020 by Quarrel Kukulcan

[Aquila Kytori]

24 minutes ago, Quarrel Kukulcan said:

I don't think it's being resized.

For the the test Jaq was supplied with a UV map with a ratio of 1:1 (1024 x 1024px).

 

So somewhere along the workflow, Uploading to Dropbox,  downloading from Dropbox,  loading it into illustrator,  creating the new texture,  exporting from Illustrator,  importing into SL and finally  applying it to the test model,   the textures is having its ratio changed from 1:1 to 2:1 (1024 x 1204 to 1024 x 512). and my guess is on Illustrator as the "culprit"  (taking as a given that, as Rey has already pointed out, textures are rounded (down) to a power of two when importing into SL

Edited December 13, 2020 by Aquila Kytori

[Quarrel Kukulcan]

(duplicate)

Edited December 13, 2020 by Quarrel Kukulcan

[Quarrel Kukulcan]

I guess Illustrator could have an automatic "crop to content during export" feature that needs to be found and turned off. I realize I've been assuming the OP trimmed the texture to just the car on purpose. I apologize.

Edited December 13, 2020 by Quarrel Kukulcan

[Aquila Kytori]

9 minutes ago, Quarrel Kukulcan said:

I realize I've been assuming the OP trimmed the texture to just the car on purpose.

 

You may have missed the clue that can be found if you dig back in the OP's post history  

( crossing my fingers I have this right  ................. ) .

[jaq Seriman]

Thank you all for your help with this. I am posting some screen shots that sort of shows what happened. At least in this instance.  Bear with me as I try to explain what happened.

When I opened the maps file in Illustrator and checked the document page size it said it was 512x512. It showed the maps in the lower half of the page which you can see in the first shot. I drew a box and made it 1024x1024 and it filled the whole page area so somehow it did not measure the image correctly as it opened. I then made the page the maps were on 512x512 and repositioned the maps to fit inside that area, image 2. When I exported this and placed the texture in sL it came out as it was supposed to, image 3. I'm not sure why the maps opened with all the white space at the top other than it was saved this way. So this mystery has been solved. Now I have to figure out why my project is doing the same thing. You've all helped a lot even though I've done this many times sometimes you overlook the obvious. I'll post some screen shots of my project once I figure out where my glitch is happening.

 

[jaq Seriman]

22 minutes ago, Quarrel Kukulcan said:

I guess Illustrator could have an automatic "crop to content during export" feature that needs to be found and turned off. I realize I've been assuming the OP trimmed the texture to just the car on purpose. I apologize.

I haven't found any settings in Illustrator that would crop content on export. If I'd export at a higher resolution it would change the resulting texture to a larger size.

[jaq Seriman]

Okay. I've gotten this to work although I don't understand why yet. The grid I placed on the car in SL I opened in Illustrator and found much the same issue as the test one. Even though the grid was named 1024x1024 it was not that size. I had to adjust the page to 1024x1024 manually even though when creating the document I told it to be 1024x1024. Very odd and I will attempt to find out in an Adobe forum why this is happening. I'm still not happy with the fuzziness of the text so I will try some other things to make it look better. Thank you for all your help and if I get this corrected I will post here. 

[Aquila Kytori]

1 hour ago, jaq Seriman said:

I'm not sure why the maps opened with all the white space at the top other than it was saved this way.

The UV 's were deliberately laid out and saved this way.

In Blender we can assign any X Y dimension (pixel size) to the base UV space. But usually it would be 1024 x 1024 for most things and especially for a car Uv's to have the maximum texture space to work with. best texture resolution. 

For this particular test dragster shell model, when unwrapped and scaled up evenly in X and Y so that it took up maximim UV space without going outside the UV space and without distortion, the UV's took up just over half of the available area. Then the UV's were moved down to the lower part of the UV space. In a full model this would leave the upper most portion available for the UV's of other parts of the same model for example the drivers cockpit and the rear wings etc. The resulting UV.png image was exported with a 100% transparent background. You should perhaps look into Illustrator as to why it lost the transparency and had a white background.

The UV space in Blender:

 

 

Edited December 14, 2020 by Aquila Kytori

[ChinRey]

15 hours ago, Whirly Fizzle said:

Also have a read of this excellent blog post by Beq Janus which explains how to get your uploaded textures looking as crisp as possible.

http://beqsother.blogspot.com/2019/02/compression-depression-tales-of.html

Wow, that was interesting! Thank you for pointing it out to us Whirly! And of course, thank you @Beq Janus for doing those tests and writing the report!

So bilinear interpolation actually gives sharper images than bicubic? That's actually quite a recolutionary discovery for texture artists. As I said in my first reply, I knew the uploader did scaling better than the Adobe products and GIMP but I thought it used FANT interpolation, not bilinear. (It would be itnersting to see a three way comparasion test between bilinear, bicubic and FANT btw).

Edited December 14, 2020 by ChinRey

[Quarrel Kukulcan]

11 hours ago, ChinRey said:

So bilinear interpolation actually gives sharper images than bicubic?

It can, depending on the exact nature of the details you're trying to maintain. Especially since SL stores textures using a lossy compression algorithm too, which might not play nice with the slightly-highlighted edges produced by Photoshop's bicubic-sharpen filter.