Art tips for illumination in cryengine3

Introduction to the art tips in cryengine3

In traditional two-dimensional art resources (such as Genie and background rendering), art personnel can directly control the final effect. The result is an interactive adjustment without having to worry about where the resources will be applied to the level in the future. Resource content is independent of the surrounding lighting conditions. Today, the observer sees the effect of the lighting model in the rendering engine. The artist can only indirectly control the final observation effect through the creation of lights, materials, and textures. It is difficult to achieve the final requirement under the demand of dynamic simulation. This is to understand the technical characteristics of the engine in order to help art personnel obtain better results outside of the technology.

Normal maps

Ideally, you do not need to use bumpmap In the GPU to implement normalmap. Even the smallest details can be obtained through geometric modeling. However, the current performance, video memory and number of triangles in detail are still a big problem. Normalmap does not need to modify the surface. They only affect shading, so that the combination of illumination and shadow is dynamic. Normalmap can be stored as different functional layers (such as 10 cm .. 0.1mm), but it will work better when the details are smaller than 3D models. Normalmaps can perform the mipmap operation like other textures. Incorrect surface details can be ignored if the colors are average. For example, the pixel points of a normalmap and the adjacent previous and next points are merged into a smooth pixel point in the next level of mipmap. Good artists can reduce this effect by avoiding high-frequency details. The use of details such as noise or texture details can also help to hide the effects of compression but to achieve high-quality compression. The normalmap effect is most obvious under the influence of highlights or reflections. Any small differences will be magnified.

Poor details of normalmap (left), good gray scale height (middle), and the final result of normalmap (right)

Unwrapping and mipmap

When you expand a model, only UV mapping is applied to solve the problem of mipmap. Unwrapping should also have a good effect on the low-layer MIPS. The following example shows a Black edge trace caused by incorrect normal when the MIPs is small. A simple solution is to create a more even background color, which is easy for normalmap In the tangent space. The most correct solution is to specify some texture element boundaries during unwraping to expand the border edge (SRF to Tif conversion under polybump) or at least fix this problem in Photoshop. The first MIP of the image in this example is good, but the second MIP already has an incorrect shadow texture element.

 

 

Tangent space

The following textures are very helpful for testing whether the tangent space of a grid is good (whether the resource and shader code are valid). They can be found under shaders/engineassets/production.

 

 

UV. DDS (top) and it are applied to the mesh (bottom) as diffusemap)

 

The following texture helps reveal the image applied there and shows the ultimate rotation of the texture space.

 

 

Tangentreference_ddn.dds (top) and it is applied to the mesh as a bumpmap (bottom)

The normalmap data in this tangent reference space represents a pyramid shape truncated by a 45 degree angle. And there is a smaller pyramid shape of the same type as him on it. This texture can be allocated to the bumpmap texture channel of the texture. With tiling (using tiling in diffusemap), it is easy to check the problem.

The tangent reference space can be used to check whether or not normalmap is attached to all surfaces. The purpose of this test is to reduce the overall illumination of the scene (for example, select the night by setting the time of day) in addition, a point light source is taken to the vicinity of the ry, and whether all aspects of the pyramid are consistent.

Good unwrapping should minimize texture cutting, which means that the angle between UV vectors is not 90 degrees. However, even the best art settings cannot completely avoid seams. Therefore, it is recommended that you replace hidden seams or areas where the model is not heavy. This can be controlled by the artist at unwarpping.

Extract normalmap from a high-modulus object

This information will be helpful for your seams.

 

Texture Image brings seams (left side) texture image no seams (right side)

Check your high-mode object to see if the same problem exists.

Do you know that normalmap is computed from one side? Is the same smoothing not used when merging the two sides?

Check your low-mode object:

Have you calculated normap for a low-modulus object? Whether the same smoothness is not used when merging the two sides, and whether your low-mode object actually corresponds to the high-mode object. For example, if they are slightly deviated, they may cause a joint.

 

Adjust the weight

To control the color of the final pixel, you need to consider where it will be affected in the rendering pipeline. There may be many ways to adjust a scenario, and this adjustment may affect other scenarios. For example, (observation direction, time of day, eye adaptive level ). This is different from checking on the final image when making a movie. For example, we want to change the color of some gray concrete because it is yellow. You can quickly reduce the yellow color through material adjustment, but this material may be applied to other places or some people need to adjust the light source to get a more gray effect. A good artist will first check the texture to see if the texture is not affected by the light. In addition, it is recommended that all textures have an approximate brightness so that a texture does not need to be adjusted during material switching. On the other hand, it is best to compress the quality of the texture with a more accurate median calculation between the brightness texture and the dark color (that is to say, it is best to retain the median for the compressed texture ). Brightness is affected by tone mapper (used only in HDR) and eye fitness (the current HDR parameter, which can be adjusted. However, be careful that only programmers can understand the impact of these adjustments. Finally, you can adjust the post-processing process (such as color grading. In order to achieve the best adjustment, we should turn off the post-processing effect, and then adjust the materials in different lighting conditions such as night, day, and fog effect.

Natural outdoor lighting

Create a bright yellow sun color, a bright blue sky color (= ambient), and an angle sun direction for better shadow under a common daylight condition. We recommend that you do not set the sun to the highest position when using the time of day function. This can be done in the terrain lighting dialog box (Arctic, Equator, and Antarctic) set some special angles to avoid this. Setting through some rotations is also a good thing, so that shadows will not be consistent with the direction of the world, will make some buildings look better, think that these buildings are often different from the direction of the world in real circumstances.

From lunar shadow

The changing characteristics of time in a day, the location of the sun, and the dynamic changes of other attributes depend on the time of the day. At night, the moon may be the only main light source. When the sun falls below the horizon, the shadow subsystem automatically uses the moon position. The system automatically fades from one State to another. If the observer pays special attention, he may notice the short shadow loss. This is because we want to avoid the Sun and the Moon computing Shadow Fading out at the same time. This process is very short and almost invisible. You can use the game design to hide this excess.

Global Illumination

Indirect light is when the light emits light on some objects and then rebounds, And the reflected surface is colored, which then affects the texture or material color. The darker the surface, the less light is reflected. A good surface has bright beige rice. The effect of blood color is the best color that is considered to be the most distinctive. A highly complex texture should be avoided because it is difficult for people to perceive its global illumination changes.

Output device color

Different reality devices (CRT display, LCD, TV, projector ,...) There are different input methods, but the same input signal is used. Their sharpness, resolution (scaling quality), latency, color, and color range are different. More differences are available in connection, cable, graphics card (x360, PS3, PC) and driver settings. In addition, the observed environment (the light reflection of windows, daytime and evening) will affect the color.

To limit these problems, it is best to provide a fixed room lighting condition to define the installer (no windows, a switched light ). Each type of monitor can quickly query the same environment. The setting should not be changed, and the setting should be verified frequently.

There is a good practice, with the development of TVs, if there is an important content of the dark color should be avoided. Because the reality of some dark colors looks the same, for example, the cropping value of most liquid crystal is less than 12/255, and the value of some poor liquid crystal displays is even more than 24/255, by adding fineness (for example, adding noise) and desaturating to an image, although the image is regarded as dark, it may gain better visibility.

Important features

Many features can be adjusted so as not to affect the results (such as dark light, dark environment color ). Generally, a poor performance is always a big problem, and some expensive features should have a good degree of use. On the contrary, such a function should be disabled because it can save some resources for other functions. If the scalability and unified performance of a product are considered a problem, some function effects may be disabled in some special settings. If the function is reduced to hide some objects, more problems may be solved. This may lead to a waste of time delay.

 

Author: Wuhua wujiu Source: wine.