Resize UV Map Texture Box?

Three65

Hello everyone,
I am currently working on a project for company that does graphics for RZR's and I have created all parts I need for the graphics so far. However I was wondering if it was possible to resize a Texture map in either Headus or 3DS Max to fit the actual size of the RZR parts I have built. I need them the actual size so they can us the UV's for the graphics on the parts. Does anyone know if this is possible?

Three65

Or is there a way that it could be tiled without having to reduce the size of the UV shells?

Eric Chadwick

One way is to get a bitmap or a vector of the layout you need, then uv to that. The resolution is up to you, just render at that size. I.e. 10 inches at 300 dpi is 3000 pixels across.

Three65

Hey Eric,
Thanks for the reply, I am not quite sure what you're saying however. I am trying to use the "real world scale" I suppose to keep my uvs at the actual size they need to be. You see I have imported vector paths to build my poly shapes from so I know they are the accurate real world size the uv/texture needs to be. I am just not sure how to get them to fit in the UV 0-1 space if that makes sense. I wish there was a way to just resize the UV space to fit the UV shell. Or maybe none of this is even possible. Seems strange that you are locked into a square at a certain size for UV's!

Eric Chadwick

Real World Scale basically bypasses the UV square, it uses world units and tiles the texture to match. One tile per meter, or whatever scale you set for that bitmap.

So I would recommend not using Real World Scale. Instead, import your path and apply a UVW Map modifier, scaling it to match the aspect ratio of your print. If you have registration marks, those would be the corners of your map gizmo.

An image of what you're working with would really help. Hard to understand exactly what you're doing.

Three65

Hey Eric hopefully this will help.

Here is a image of the Illustrator paths that they use to cut the graphics.
Take for example the very front of the hood, front center. It is 491.612 mm by 233.937 mm
which is roughly 19in x9in. This is the path I imported into 3D max to make my poly parts from so I knew they was the correct size.

[IMG][/img]

After going through and building out my parts with the paths they provided I would like to keep them at the real world size so that I can import them into Zbrush or 3D coat and poly paint them so I have control over which parts of the design land where. This will give me a accurate way of following body lines ect. Along with previewing the designs before they are printed to see what kind of flow the design has. Below is a image of the hood paths along with the poly objects I built to match them to try and achieve this.




I then bend the poly parts to match the body lines of the RZR and export them out as OBJ's so I can create the UV's for them in Headus. Once I import the object back into make and put a Unwrap UV modifier on it this is what I get. But when I render it out say at 4k it still doesn't come close to matching the path in Illustrator. So what I need to be able to do is ploy paint these parts and export the poly painted textures while not loosing the resolution/size of the original poly object that I created from the start.

[IMG][/img]

Eric Chadwick

Crop that first white image to the extents of the 491.612 mm by 233.937 mm area you want to print. Save that as a png, then drag it onto a Plane primitive in 3ds Max. Scale the plane until it matches the mesh you made from the paths. The plane is now the size you want your uvs to be.

Three65

Sorry I am not quite fallowing what you're trying to say. Are you suggesting I use the plane for the textures? Since the poly object is already the size I want the UV's to be why would I need the plane?

Eric Chadwick

If I understand the situation correctly, you need to make a set of image files at a specific size for printing. Each image must fit its specific pattern template, which was given to you as paths. What I'm saying is to use the Plane to determine the rectangle extents for each design, then use that as your uv for the pattern you create. The Plane can be used to Render Texture from the design you make, onto the Plane, "baking" the design into a print image.

More about baking here:
http://wiki.polycount.com/wiki/Texture_Baking

Eric Chadwick

Thinking about it some more. You have these separately printed designs, but you want to design them all together as a cohesive whole, on a 3D model, right?

So then you should build a 3D model, with each design as a separate part. Then you can use Texture Baking to convert each 3d design into a printable image. The trick here is making suitable "low poly" models to bake into. They need to match the aspect ratio of each design's template.

Three65

Ahhh I think I get what you're are saying now Eric, As you can see from the middle image I already have some pretty low poly parts build for each separate part. I just need to finish bending them in the right angles to match the body lines of the RZR. Once I get this done I can poly paint all those parts and bake each of the poly painted parts textures out onto a flat plane to give me the design I need for the Illustrator files to use. Is that correct?

Eric Chadwick

Yes. Except you need to make UVs for the lowpoly parts, and those UVs need to match the size of the intended output. If you load your registration marks into UVW Unwrap, as a background bitmap, then you can adjust your lowpoly UVs to match. Then you can bake the polypainted models into the lowpoly UV layout.

Three65

Ok I think I understand what you're saying, so it doesn't matter if the size of the UV for the lowpoly fits in the 0-1 UV space just as long as it matches the texture I import into the UVW Unwrap it should work?

P.s. Thank you for taking the time to help me get this figured out, I really appreciate it.

Eric Chadwick

It does need to fit entirely within the UV space, otherwise the image will be cut off (or tiled). Not what you want in this case.

Make a bitmap in Photoshop that has the vector in it, and whose dimensions match the print size you want to output. Load that in Unwrap (upper right corner of the Edit window, it says CheckerPattern). The UV square will resize to match the bitmap aspect ratio. Scale your UVs to fit inside the UV 0-1 space (formerly a square) and to match your original vector shape.

Three65

Eric,
I just wanted to thank you for taking the time to explain this to me and help me with this problem. I created the bitmap like you said and imported it into the Unwrap which scaled the UV space to fit my object. I have been pulling my hair out for 2 weeks searching google trying to figure out how to do this. Now I just need to read up on baking and try to polish my workflow for this project. Once again I can't thank you enough for helping me with this and it just goes to show what a great place Polycount is for help.

Eric Chadwick

Great news. Good luck with the project, and let us know how it worked out.