Overview

After completing this tutorial, you will be able to create a skybox with SkyPaint, but the textures themselves will still need to be organized a certain way in order to be recognized in Sandbox correctly.

Getting Started

While it is possible to create a skybox using 3ds Max, this tutorial only describes the use of the SkyPaint tool for creating skyboxes.

The first step is to install SkyPaint and its Photoshop plugin in the right directory.

The Photoshop plugin is required, as SkyPaint itself is nothing more than a viewer/projector for the image files, which exports/exchanges everything with Photoshop.

SkyPaint will project planes properly onto a cube, stretching and distorting the planes like a lens so that it is impossible to spot the seams at the edges of the box. Skybox shows a globe, while it is in fact just a distorted cube.

To help you get an impression of how it works, look at the following picture:

The upper two shots are the 2D planes/faces that get exported from SkyPaint. As you can easily see, they are distorted at the outer edges, especially near the corners.

The lower screen shows the same area as a projected cubemap. It should be visible that the projection helped make this cubemap not look so cubic, so you can rotate around and won't recognize the corner areas.

The big problem with the projection based system is that the more often the view is changed and projected, the more blurry it will get. So, try to limit the use of it, and finish your work while avoiding moving between SkyPaint and Photoshop. If you really need to, you can avoid blurring by using bigger sized working files (2048x2048 per face).

Preparing the Cubemap

Open SkyPaint and select file/new to generate a new skymap. It will ask you about the size and you can assign some predefined templates.

Change this size to 2048x2048 and press enter (no need for a template). Now select file/save as and save it as a targa (.tga) file, under a name that is easy to remember.

SkyPaint now creates 6 different pictures for each side of a cube with a specific name. As soon as it's saved, close SkyPaint.

Now open Photoshop and create a new image with a height of 1024 and a width of 2048. Fill this image up with red color. Now, extend the canvas to a height of 2048 and color the new part with black.

You now have an image split into 2 equal parts. The line where both parts touch is the horizon and more or less the area where you should start to work on.

Now save this image over all tga´s with "_LF","_FR", "_RT" "_BK" in their names. You have now replaced the 4 sides (left, front, right, back) of the cubemap. Now re-color your image fully red and save it as "_UP", for the top part of your cubemap.

Just keep the original "_DN.tga" as it is so that you can easily see the corners while watching the skybox with SkyPaint.

You now have the perfect base for starting to work on your skybox.

While you're working, you should have Photoshop and SkyPaint running at the same time.

Using SkyPaint and Photoshop

Start SkyPaint and open your saved file, and you will see the skybox.

If you click and keep holding the left mouse button at the viewport window you can move around and change the view. The arrow buttons have the same functionality.

As soon as you have found the area where you want to work on, click on the painting icon (or hit the enter key) on top of the viewport. You will be prompted to give dimensions for the projection. Type in 2048x2048 and proceed with OK. SkyPaint will transfer the bitmap data over to Photoshop. Photoshop will pop up and you can continue working there.

Now, you can paint freely, insert photos, apply gradients and all the other things that you will need to do to create your sky. The only limitation is that you need to collapse all your layers as soon as you are finished because SkyPaint will only accept the background layer for the transfer back.

You can transfer your work back to SkyPaint by starting the SkyPaint plugin using the filter menu of Photoshop. Now the bitmap data gets transferred back to SkyPaint and you can see the result.

You will have to constantly switch between both programs, changing the view with SkyPaint and painting in Photoshop on the target area.

Preparing for use in Sandbox

In order for your skybox to properly be recognized in Sandbox you will need to save the files in a certain way, please refer to Skybox Texture Setup for more information.

使用 SkyPaint 创建天空盒

此教程结束后,您将能够使用 SkyPaint 创建天空盒,但是为使 Sandbox 能正确识别纹理,仍然需要将纹理以某种方式组织。

入门知识

虽然使用 3ds Max 可以创建天空盒,但是此教程只描述使用 SkyPaint 工具创建天空盒。

第一步是将 SkyPaint 与 Photoshop 插件安装在正确的目录下。

Photoshop 插件是必需的,因为 SkyPaint 本身只不过是一个图像文件的 观察器/投影机,SkyPaint 使用 Photoshop 导出和交换一切文件。

SkyPaint 将平面正确地投影到一个立方体上并将平面像镜头一样拉伸和变形以达到在盒子的边缘看不到接缝的效果。Skybox 显示了整个世界,而它实际上只是一个失真的立方体。

为使您对天空盒的工作有一定的印象,请看下面的图片:

上面两个是从 SkyPaint 导出的 2D 平面/正面的镜头。您能清楚地看到,镜头在外缘,尤其是角落处失真。

屏幕下方显示了和投影的立方体贴图相同的区域。这些区域应是可见的,投影使立方体贴图看起来不是那么立方,因此您可以将其旋转且识别不出角落区域。

基于投影系统的大问题是被更改和投影得越频繁,视图就会越模糊。因此,尽量限制其使用,工作中避免 SkyPaint 和 Photoshop 之间的频繁切换。如果真的需要切换,为避免模糊,请使用更大尺寸的工作文件(每面尺寸 2048x2048)。

准备立方体贴图

打开 SkyPaint 并选择文件/新建以生成一个新的天空贴图。系统将询问贴图的尺寸,您可以指定一些预定义的模板。将尺寸更改为 2048x2048 并按 Enter(不需要模板)。选择*文件/另存为*,将其作为 targa (.tga) 文件保存并为其输入一个容易记住的名称。

现在,SkyPaint 为立方体的面创建了 6 个不同的图片且每个图片有特定的名称。保存后请关闭 SkyPaint。

打开 Photoshop 并创建一个高度为 1024、宽度为 2048 的新图像。用红色填充此图像。现在,将画布高度伸展到 2048 并使用黑色给新的部分涂色。

图像被分成两个相等的部分。两个部分都能接触到的区域就是地平线。差不多这就是您应该着手的区域。

Now save this image over all tga´s with "_LF","_FR", "_RT" "_BK" in their names. You have now replaced the 4 sides (left,front,right,back) of the cubemap. Now re-color your image fully red and save it as "_UP", for the top part of your cubemap.

保留源文件 "_DN.tga" 以便使用 SkyPaint 观看天空盒时能清楚地看到角落。

有了这些基础您就能很好地使用天空盒继续工作了。

工作时,应同时运行 Photoshop 和 SkyPaint。

使用 SkyPaint 和 Photoshop

运行 SkyPaint 并打开保存的文件,您就将看到天空盒。

在视口窗口中,如果单击并保持按住鼠标左键,就能移动和更改视kou。箭头按钮也有此功能。

找到要工作的区域后,单击视口顶部的绘制图标(或按 Enter)。系统将提示您为投影设置尺寸。输入 2048x2048 并按*确定*。SkyPaint 就会将位图贴图数据传输到 Photoshop。Photoshop 将弹出,您就可以在那里继续工作。

现在,您可以自由地绘制、插入照片、应用梯度以及做创建天空需要做的所有事情。唯一的限制是完成后需要将所有的图层折叠,因为 SkyPaint 只接受传输回来的背景图层。

通过运行 SkyPaint 插件并使用 Photoshop 的筛选菜单就可以将工作传输回 SkyPaint。位图贴图被传输回 SkyPaint 后,就能看到结果。

您需要在这两个程序之间不断切换:使用 SkyPaint 更改视图,在 Photoshop 中的目标区域绘制。

Sandbox 中的使用准备

为使 Sandbox 能正确识别天空盒,需要以某种方式保存文件,更多信息,请参考天空盒纹理设置