Last modified on 20 October 2009, at 11:55

Wings 3D/User Manual/UV Mapping Mode

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� WINGS3D USER MANUAL Section 5.2 6 AutoUV Mapping Section 6.3 UV Mapping


The UV Mapping Segmenting Mode window. Note the new menu available in this mode. Here you will divide up your model into slices called charts which will be laid out on a texture map. You can hand create the charts or have wings do it for you.

UV MAPPING | SEGMENTING MODE

There is a new step in the autoUV, called 'segmenting'. You use the segmenting step to create charts and cuts. A chart is an area (a set of connected faces) of your model that will be mapped to a 2d surface as a separated area. You can let Wings do the work for you by clicking continue or if you want more control you can do it yourself in this window. This sections explains how.

When you enter the segmenting step, you'll have the model’s materials as your charts, you can use them as your charts by pressing 'continue'. You can also do it by hand to have more control over how the charts are

created. Select faces and choose one of the AuvChart[1-9] charts. If two, or more, groups of selected faces use the same AuvChartX they will treated as two, or more, charts if they share no edges. In this way you can create more than 9 charts.

Continue

Despite being on top of the list Continue will be the last thing you will do. When your satisfied with your charts (and cuts if your are going to use the unfold algorithm). Press 'continue' and choose the 3d to 2d mapper; method. Projection or Unfolding.

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� Section 5.2 6 AutoUV Mapping WINGS3D USER MANUAL Continue | Projection

Projection computes the weighted normal for the chart (larger faces contribute more to the normal than smaller faces) and projects the 3d to chart on a 2d plane (This was the method used in the old autouv). Projection needs almost flat charts (2d planes) to be able to create a good 2d mapping. It will also use your materials as a guide to breaking up your model into smaller charts.

SEGMENT BY | PROJECTION

Continue | Unfolding

Unfolding computes a 2d drawing by unfolding the model mathematically, this method should be used when your charts isn't flat (close a 2d plane). If you have bad charts and cuts the unfolding algorithm may produce strange results, but provided good charts and cuts in the right places, the result should be acceptable.

When the mapping 3d to 2d is done you end up in the autouv window, which works as before.


There are basically three ways you can segment (or cut up) your model for UV mapping. Two of them are so fast and easy as to truly merit the name AutoUV. The third method is not much harder, once you get the feel for it, and much more suited for complex models. We will discuss the first two methods first, and save the third for last.

If your model is fairly simple in nature (such as my smoothed cube) it is a good candidate

for using one of the truly automated methods of segmentation. If you choose Segment By you will be given the choices of Projection or Feature Detection. Choosing Projection will segment the model so that faces are chosen based on which of the six primary axes they most closely approximate. Below you can see that my smoothed cube has been assigned six materials based on their orientation. This should minimize stretching in the UV map.

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This option will automatically segment your model into the minimum number of charts necessary; often just two. Below you can see that my smoothed cube has been assigned two materials, breaking the model into two nearly equal sections. While this is very fast and easy, it could lead to layout and/or stretching problems later, when trying to paint the texture on the resulting map.

AuvChart1~9

Charts should be created with care, they should be used to minimize the stretching and still contain something that you are able to paint. Fewer charts is better from a user perspective because they are easier to paint on, but more charts will lay flatter so they will have less texture stretching. You will have to deside how best to divide the surface so that it is as flat as possible.


Note that I picked up where I left off, that the smoothed cube starts out here projected. You can switch back and forth between the two as long as you do not choose Continue.

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� Section 5.2 6 AutoUV Mapping WINGS3D USER MANUAL Creating Cuts


The Segmenting Right Click Menu

The third option is to segment your model by hand. The task is to break up your model into as many charts as you need in order to make your model lay flat. A flat model will not have texture stretching, but if you make too many charts you will not be able to easily paint your textures. The art of proper chart number to ease of painting is a skill learned with practice. Once you have finished making your charts and appropriate cuts you click Continue | Unfolding

Mark edges for Cuts

A 'Cut' is used to simplify a chart for the UV Mapper to correctly spread out your charts on the texture. If you want to unfold a cube in one chart, you can do that by cutting the correct edges, or if you want a spherical or cylindrical mapping you must have cuts. A spherical mapping is done by making a cut between the poles of the sphere. And a cylindrical mapping is done by making three charts, two discs, one with a cut. See the image on the right.

Quick Tip: Using Cuts

In the cube example, there is only one chart. I selected the edges that are green and used


the command "Mark Edge for Cut". I then choose "Continue | Unfolding".

In the cylinder example, there are three charts. To have the middle part of the cylinder unfold properly, I have marked a single cut along one vertical edge. In this case I simply used "Segment by | Feature Detection" which created the charts and the cut automatically. I can keep the layout it gave me or do some minor edits. Once done I click the Continue | Unfolding.

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Once you have decided on how to segment your model (via Projection, Feature Detection, or by hand) then you can use the Continue option. This will bring up a new window titled AutoUV, which will contain the

Quick Tip: Is having more charts better

I think the general rule is that fewer charts gives more stretching per chart but are easier to paint. Both these ops gives the user an initial suggestion, which they can alter, but feature detection shouldn't be used together with projection parameterization. Projection segmentation often gives more charts than feature detection.

Quick tip: Updating the UV Maps after edits to the mesh

Here is a tip that might not be obvious.

Let's assume that you have done some changes in the segmenting phase. You might have recolored faces or cut edges. You then do "Continue | Unfolding" and find that the

layout for your texture map. In the example above you can see that I had done my segmenting by Projection (left image) and then by selecting Continue an AutoUV map comes up (right image) with the model nicely laid out.

result is not quite what you expected. For instance, you might want to have chart cut or split in two.

Currently, there is no way to go back to the segmenting phase directly. But the following trick will work:

1) Quit and save all changes. 2) Use the "UV Mapping" command again. 3) You will be asked whether you want to edit the current UV mapping or discard the current UV mapping and start over. 4) Choose the second alternative -to DISCARD the UV mapping. The texture and UV coordinates will be discarded, but before they are discarded, AutoUV will use them pre-color faces and insert cuts according to the UV coordinates. 5) Do the needed changes.

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� Section 8: Plug ins WINGS3D USER MANUAL AUTO UV WINDOW


Once you have your charts in the Auto UV window you can further tweak the position of your charts to make it easier to paint them without getting stretching. You have a small selection of tools with which to edit the charts. All edits affect the entire chart. Currently there is no way to reposition vertices directly in this window.

Move

Move allows free movement in the whindow.

Scale

Scale only allows uniform scaling.

Rotate

This gives you the following options

Z Free

Z 90 deg

Z -90 deg

Z 180 deg

X 180 deg

Y 180 deg

Rescale all

Place objects in the lower left hand corner of the texture (the square). Rescale then tries

to squeeze everything else back in to fit on

the texture. ReMap UV This has three options. Project normal –Projects chart normal. UV from Unfold ? Stretch Optimization – ? Project normal and unfold . Draw Options These are the settings for textshowing textures and colorsbackground. And others. ure in size, the Apply Texture

Applies the texture to the object. (you will need to right click on the AutoUV window to close it.

Quit

Quits out of the AutoUV window and asks if you want to discard or keep your texture.