How many textures?

[shmbry18]

I,m in the process of doing various experiments with unwrapping and painting. before I get far down that road I'm still trying to decide how to layout the UV maps and as a result how many textures I'll need.

Being a novice in this area I'm basing my thoughts on the following:

If I want a clean line for panel lines etc, that line should be no wider than 3mm - 1/8" in real life. The thinnest line I can create is 1 pixel. Therefore if my fuselage is 68' long I need 6909 pixels (Metric) or 6528 pixel (Imperial) to cover the length of the fuselage at that scale.

The aircraft is for P3D v4 and although the SDK says 1024 x 1024 I have seen aircraft in there at 2048 x 2048. So following that logic I need to spread the fuselage over 3 x 2048 and 1 x 1024. The smaller parts or parts requiring less detail can go on smaller textures.

But I don't want to keep rearranging maps juggling what goes on what texture. I'd like to get an idea before I start in earnest, even possible sketch with paper and pencil to come up with a strategy.

Am I thinking along the right lines? (no pun intended)

 

[tgibson]

At what resolution do you display P3D, and what is the size of your moniitor? I don't think you will see a 1/8" line in FS, it will be essentially invisible. I would set up a small test object (a simple cube) and texture it using that pixel density. Then try creating your panel lines and determine if you can see them. I would bet that you can cut the size of your fuselage mapping to 4096 pixels (which I believe P3D can handle?) and it should be fine.

 

[shmbry18]

Hi Tom

Good point. I'm running P3D and monitors at 1680 x 1050. I have made a couple of cubes testing various pipelines, but I just threw some paint at them. I'll do some more precise tests.

 

[n4gix]

What I've done in the past when I had to do my own painting, modeling and gauge programming, was to create a template consisting of matrix of 2x2 squares of the final size I wanted to have in the sim. In other words, if I wanted to use 2048x2048 pix external bitmaps, my template would be 4096x4096 pix.

I would then UVW map the fuselage, wings, etc. on that giant template, export the UVW'd mesh layer and use it as the painting surface. When done, I'd slice a copy of the painted template into four separate bitmaps for use in the sim.

Keep in mind though that since P3D will accept up to 4096x4096 pix bitmaps, you could also double the size of the template to 8192x8192 pix and end up with only four 4096x4096 bitmaps. I'll wager that you could easily fit everything you need on those four bitmaps.

Alternatively, nothing says that your bitmaps must be "square". If you think it will work, use 4096x2048 for the fuselage...

There are many different ways to accomplish your end goals.

Hint: try hard to avoid rotating things on the bitmap at weird angles as it makes lining up the cheat lines a pure bitch!

 

[shmbry18]

Hi Bill

Thanks for that, you've clarified a point I had in my mind. I had thought of do so but was confused, I wasn't sure if, having cut up the template, the pieces would retain their original coordinates, but I've final got it into my head that the mapping relies on the UV coordinates and not coordinates based on the number of pixels. So U1 V1 is still the same irrespective of texture size.

Having said that I'm not sure how that works out if you go from a rectangular to a square texture. Or if the part was mapped at U1,V1 on a large texture but ends up at U0,V0 on the cut piece. Would the part still want to texture at U1,V1 on the cut piece?

I've also looked at UDIM, I'm currently thinking of experimenting with Modo which supports that (plus I find the lack of paint layers in Blender a pain, I think node editing is an over complication for what I'm doing)

I know you can UDIM in Blender, and have done so, but I haven't found a way of display textures at coordinates other than U0,V0.

 

[ozzman1997]

To get the correct sizing, one thing you can do is apply a bitmap to your object while unwrapping that visually shows you what the final resolution will be like. You can find a bunch of them on Google images, but most aren't 4096*4096 in size...so you can either find one and tile it in a higher resolution, or create your own in Photoshop by just patterning a 2x2 checker pattern with numbers or letters as shown below:

This is especially useful for making sure text and logos will be clear enough on your textures. Obviously you can use more than just 4 characters as well, but I've found that this works well enough for my purposes. It's also great for avoiding distortion in your UVs, which can sneak up on you if you're using larger checker patterns or ones without text.

I don't have any "scientific" method for deciding how many sheets my fuselage will be spread over, but simply creating a plane mesh that is divided into even squares and aligning it with your model from nose to tail in the side view can give you a good idea of how many it will take. This also depends on whether or not you plan on mapping the top and bottom of the fuselage, since generally they are mapped as planar left/right, cylindrical (PITA unless you have Substance Painter!) or planar top/bottom/left/right. Then I create physical cuts in the model where each square comes together, which will become the edges of my UV map. I'm not sure if Blender lets you specify the exact size of a planar UV projection, but typically what I do in Max is use the "measure" tool to determine how large my maps are going to be by measuring one of the squares, then apply a planar UVW map modifier with those exact dimensions at the front section. If all goes well, your mesh should be mapped perfectly from U0,V0 to Un,V0, where n is how many cuts you had to make. Then you can create your master PSD in Photoshop containing all of the maps, aligned front to back, with guides between them to make cropping and saving each "tile" as easy as possible.

And to emphasize what Bill said above, there are many ways of achieving the same goal! And I'm sure that someone out there has a more efficient method of doing this than either of us do.

 

[n4gix]

When you are ready to UVW map, create the size of the UVW with the same ratio as the desired end result. IOW, if you map as a rectangle, then the bitmap in the sim must be a rectangle as well.

 

[shmbry18]

Next experiment, a 20' cube textured with a 2048 x 2048 using lines of 1 pixel wide.