PDA

View Full Version : Understanding UV Map Resizing



steamthunk
01-17-2006, 09:33 PM
Hi. I've been slowly teaching my self LW8.3 following the Dan Ablan Inside Lightwave 8 book. I've come to a part where I'm applying a planar UV map to a cellular telephone model. My problem is that when I load a tga image to be my image map it doesn't align with the UV map mesh (which is stretched horizontally when viewed from Top).

The tutorial mentions that I can use the stretch tool to "squeeze the UV map in to match the shape of the phone.", but it's not clear whether I'm supposed to do that or if it was just trying to make a point about the feature. It seems like I have to do something to scale the UV mesh, but my question is how would I get it to exactly match the shape of the model? I haven't found any way of inputting numbers (or even how I'd get the *precise* size/location of my model).

Hopefully this is not too confusing for someone to point me in the right direction.

SplineGod
01-17-2006, 11:20 PM
Normally you would capture the UV map as a screen capture in modeler and then crop to the edge of the UV grid or export the UV map using the EPS exporter. There are also other unwrapping tools but those are the two most common ways. Once you have the UV map saved out as an image you use it as a template to create your texture maps.
If done properly the image should fit the UV map correctly when imported into LW.

You could use the stretch tool assuming that the problem is easily fixed that way. For precise placement you have to manually move each vertex in the UV map to match the image map. I would think that this would be explained in the tutorial (I dont have the book).

Rory_L
01-18-2006, 06:07 AM
I haven't found any way of inputting numbers
I am not particularly recommending that you edit your UV map this way, but...

You can access and edit any vertex`s UV coordinates via the information panel [i]. Select the points you want to edit, hit i on the keyboard and the info panel comes up, towards the bottom of which is an `Edit Value` drop down list. This defaults to `Position`, but you would change this to `Texture` to be able to edit the UVs.

Cheers,

R

steamthunk
01-18-2006, 10:08 AM
I will try to put some pictures up later when I get home, but I was wondering some basics. I started this model by using a background image of a mobile phone in the top view. Then I built geometry on top of the image backdrop. Should the UV map then essentially be resized to match my initial background image (assuming I built geometry without deviating from my background dimensions)? Should this be done in Lightwave or after the EPS export? Or is it the other way around and I should be stretching my image to match the UV mesh?

Sorry for all the newb questions. This seems confusing to me. 8~

SplineGod
01-18-2006, 03:13 PM
Two ways you can do it:
1. You can use the UV map that you have flattened and adjusted by hand to generate a template that you can export to a paint program as reference to create your image map to match up to it.
2. You can adjust the UVs to match a preexisting background image.

I also have a couple of free videos on my site showing basic UV mapping.

steamthunk
01-18-2006, 10:13 PM
Thanks for the tips. Your videos are very helpful in understanding this stuff more! :) I'm still not 100% sure about my specific case. After loading the completed model from the DVD I noticed that the UV map there was sized differently so I can only assume that I was supposed to stretch the UV into the shape I needed and then loaded the texture.

Unfortunately, I spent the night fighting with some kind of layout "crash" problem and didn't get much work done. :(

SplineGod
01-18-2006, 10:28 PM
Well Im glad to see that youre at least getting a better feel for UV maps. :)

roboanarchy
01-24-2006, 03:33 PM
I think the best way for you to do this is to use the Surface_Baker. UVMap your whole object - I define all my surfaces very finely and that way I can just use an atlas UVMap. You then surface your object however you want - image, procedural, shaders. Load it into layout and go to the shaders tab of the surfaces panel and load a surface baker, doesn't matter which surface you put it on since it works on the whole object. Set up the baker how you like, then when you hit F9 it will render a UVMap texture that when you apply it wraps perfectly around the object. If you need more detail there are tutorials all around.

I pretty much use this for everything now because its sooo easy and you end up with the same result. A little touch up work on your bitmap and voila.

peteb
01-26-2006, 11:08 AM
Are they ever going to fix the EPS exporter so it exports the shape of polys in sub P mode? At the moment you can only export in poly mode.


Pete B