User:Wolfsbane/Sandbox

Converting New Models for Darkwind

A quick step-by-step guide to turning a Sketchup model into a Darkwind model. This isn't very detailed, because I'm not an expert in Blender, so you probably don't want to learn my bad habits anyway. Also you may prefer to use another 3D modelling package, in which case detailed instructions won't be much use to you. Either way you need to learn (or know) how to use a 3D modelling package before we start. I picked up enough blender to be useful in a few evenings of following tutorials, so it's not a huge issue. All the tools we'll be using here are free, so that's no barrier either.

Software

You will need:

Blender - or your preferred modelling software. It needs to be able to import Collada format models (.dae) and export Wavefront objects (.obj).

Sketchup, Google's free modelling program.

First, Catch Your Model

You'll need to find the model you want to convert on sketchup. Have a look through the 3D Warehouse. There are a few things to take into consideration:

Technical

• Is the model too detailed? Check the download size, anything over 5Mb is probably off limits. If the model is "tuned" (spit), try and find the original.
• Can Darkwind support it? Four wheelers with enclosed cabins only.
• Is it possible to texture it? We'll look into this in detail later, but for now the closer to a simple cube it is, the better.
• Is it legal? Models on sketchup can be used for pretty much anything, but I'd steer clear of anything with comments like "found on the web", or anything ripped from another game (obviously).

Aesthetic

This is more about whether your model will ever make it into the game. Making something that fits with sam's vision of the world gives you a much better chance. I'd avoid one-offs, made up cars or kit cars. Modern cars are lower priority than 60s and 70s style, and anything unusual tends to be better. There are any number of 70s muscle cars, for example, but I haven't bothered converting any because there are so many in the game already. Except for the Capri, obviously. I never said I followed all the rules :)

Our Example

For this tutorial, I'll be using this Chevy Suburban, spotted by Knight. This passes pretty much all the tests above, except possibly being a bit close to an Apache. I suspect the differences are enough though.

Stripping

There are two main steps to take us from a Sketchup model to a Darkwind model. We need to reduce the poly count to 1500 from whatever it starts at (often 20000 or more), and then we need to texture it with a single 512x512 texture. To start with, we'll reduce the poly count as much as possible by deleting everything we don't need from the model.

Download the model, and open it in sketchup. Select XXX from the menu to see the poly count. Currently it's XXX (this is not accurate for a variety of reasons, but it's a reasonable estimate). Now select Outliner from the XXX menu. This lists all the separate objects in the model. Click on one and it will be outlined in blue. Click again and everything else greys out, so we can see exactly what we're doing. Obviously the first thing we need to do is delete one of the suburbans.

Next we'll go through and remove what we can. Wheels aren't needed,

Now that we've got rid of everything we can, it's time to export to blender for the more detailed work. Select everything on the outliner, right click and choose "explode". This may take several minutes, so be patient. If there's anything left, explode it again. Keep going until the outliner looks like this:

Now select XXX from the file menu, and export the model. That's it for Sketchup, so feel free to close it and open up Blender.

Will It Blend?

To import the model into Blender, go to XXX, and choose Collada 1.4(dae). The import dialogue will appear in one of the windows - if it's too small to see, ctrl-up will maximise the window. Choose the file you want to import, press the "Delete XXX" button, then press "Import and Close". You should see your model appear after a short pause. If you don't it may be too big to see - press a, then s, then move the mouse until it appears and press the left button. Next, clear the parenting information (XXX). This avoids some problems with rescaling parts of the object.

You can see the current poly count in the top bar. Right now it's XXX, and we need to get it below 1500. You're mostly on your own here, but there are a few tricks I've found along the way.

More Deletions

You should find the model is grouped into objects. I don't know why these don't show up in Sketchup, but whatever. Delete everything you don't need. Hiding things temporarily helps you get at the inside. You could also try hiding everything you want, then deleting what's left. Make sure to remove all of the interior - we don't need it, so it's all wasted space.

Double Skins

The export from Sketchup makes everything double sided, which means we have twice as many faces as we need. Sometimes you can select these by material, and sometimes you just have to use the remove doubles tool, then clear up the mess afterwards. Auto recalculating normals works pretty well for simple objects.

Window Cleaning

Remove anything that would look just as good painted on - especially logos. Windows etc. are better as part of the texture, because it makes it easier for artists to modify later. Here I'm stripping out the side windows.

Auto Reduction

There are two ways to automatically reduce the poly count. One is easy to use but gives pretty bad results - XXX from the scripts window. I used this on some of the earlier models, but I try to keep it as a last resort now. The nicer way is the decimate modifier. Because it's a modifier you don't lose data, so you can add modifiers to each object separately until you get the poly count you want, then apply them all. The only problem with decimate is that it only works on XXX objects. You can use ctrl-alt-shift-S to select non-XXX vertices, which helps a bit, but it's still a pain. The results are good though.

Tidying Up

Once you're close to 1500 polys, you also need to make sure your model is clean. By this I mean there should be no holes, no stray edges or faces, and no weird geometry (infinitely thin edges, etc.). It's up to you how far you go with this, but it'll make the texturing easier. Once you've finished, save to a new file (because the next bit is irreversable) and apply all your decimate modifiers. Then select all objects and join them together. You should have a single object consisting of a single closed surface. With that done, it's time to start skinning.