HINT AND TIPS FOR QUICK CREATION OF COLOUR-ENABLED OBJECTS
by Numenor and JWoods

First of all, let me give a big Thank You to JWoods, that not only has written the part related to the mesh editing, and volunteered for answering to your question on this subject, but also has made me understand what happens to the .obj file from the moment it is extracted from the GMDC to the moment it is reimported in the package. :)

As you all know, in order to create new objects and to enable colour options for them you can follow the Mesh Tool tutorial and the Colour Options tutorial.
Though these tutorials are good, still sometimes may happen that the new object doesn't work as it is supposed to.
As a matter of fact, some parts of those tutorials should be explained better, some other should be changed, and some can be totally omitted.
This notes will help the creators in building objects in a quicker and easier way then before, cutting off most of the troubleshooting phase and the colour-options enabling procedure.
We'll still refer to the existing tutorials, when needed.


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Before you start: CHOOSING THE RIGHT OBJECT TO CLONE

If you want to create a new chair, you can't simply clone any existing chair: you have to find an original chair that has a mesh structure as similar as possible to the one you are going to create.
If you have a new mesh that is composed by two different parts, each one with its own texture and UV-map, then you have to find an original chair that has the same structure.
To look at the mesh structure of an original object, you have to create a temporary clone of it: to make things easier, when cloning the object, leave all the cloning options unchecked.




When all the files are collected, select the GMDC and check the number of the meshes listed under "Models" (don't count the "shadow" ones).




If you're not satisfied, check another object.




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Next step: CLONING THE OBJECT

When you have found the right object to clone, open againt Object Workshop and select the choosen object; this time, check all the cloning options and then click "Start".




The Scenegraph Rename Wizard will appear




Look in the "ModelName" field: SimPE suggests a unique name for it, but it's always a good thing to rename it. Choose a new ModelName with the following pattern: yourName-objectUniqueName-date; the ModelName must be unique, but nevertheless not too long. Don't use underscores; when you're done, click "Update" and then "OK".
(I know, the MeshTool tutorial suggests not to rename anything, but trust me, assigning a new unique ModelName is better...)




Now you have to select the GMDC and take note of all the meshes listed in the "Model" list: we'll need them later on.




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EXPORTING/EDITING/REIMPORTING THE MESH

For this phase, you can follow the official Mesh Tool tutorial: start with Page 3 (registering a new GUID for you object) and go on until you complete Page 7 (reimporting the altered GMDC into the package).
IMPORTANT: follow the Mesh Tool tutorial only from Page 3 to Page 7; do not perform step 8.

Jwoods has something important to add about the "shadow" mesh parts (groundshadow, eastwallshadow, etc.): it's always advisable not to delete them, either when exporting the object from the original GMDC, or when editing the mesh in the 3D program. On the contrary, adjusting (scaling) and positioning these shapes around the custom object in the manner they were on the original object results in more appealing shadows. If you delete the "shadow" meshes, your object is likely to not cast correct shadows, or not cast indoor shadows at all.


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RESTORING THE ORIGINAL MESH STRUCTURE

This phase is important because doing this you actually restore the original colour options, without having to follow my Colour Options tutorial.
Remember those mesh names that you have written down earlier? Now they come at hand, because you have to open the GMDC ("Items 3" tab) and restore the original mesh names (e.g. in the 3D program you have replaced the "fabric" mesh with the "cushion" mesh? Now you have to rename the mesh from "cushion" to "fabric"). Commit and Save.




Basically, you're done. You have just to replace the original textures with the custom ones you created for your object, and perform the "Fix Integrity" once more.
IMPORTANT: you can use the "Fix Integrity" as many times as you want, as long as you don't rename anything and don't click "Update"; just click "OK".


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TESTING THE PACKAGE

As JWoods strongly suggests, the first thing to do is to select the GMDC and click on the "Preview" button: this instructs SimPE to collect the materials (Texture and Material Definition) and render the new mesh, just like the game would do. If you find that some mesh parts are plain white, this means that there are problems with the materials for that mesh part (in the game, that part will appear flashing blue).




If you have a correct preview, save the package, start Object Workshop once more and select the "Load Object" tab; select your newly created package and create a simple recolour for it. Copy both packages in the download folder and fire up your game: you should have a colour-enabled object, with an additional recolour for it.
If something is wrong with your new object and/or the recolour (invisible object, flashing blue textures, object using original Maxis textures instead of yours), remember that not all the original objects are perfectly suitable for cloning and re-meshing. For instance, all the beds "borrow" the beddings from the Colonial Ironwood Double Bed: if you cloned the cheap single bed, don't expect it to use your custom beddings. :)
A complete list of objects that "borrow" the textures from other objects can be downloaded here.
Lastly, if you can't find what's wrong with your object, you might want to read my Troubleshoot Check-list and the Colour Options main thread.

Feel free to post your questions here on SimPE forums or onto this thread on MTS2: JWoods will answer about the mesh editing, and I will help you with the colour options and the package structure.