限制

Eevee的目标是成为一个交互式渲染引擎。在不影响性能的前提下,一些功能还没有加入或不可能整合进Eevee的架构中。

以下是在使用Eevee时你可以预见到的功能限制的详尽列表。

相机

  • 目前只支持透视和正字投影。

灯光

  • Shadows are not supported on light instances (instance objects, group instancing).
  • Eevee场景中仅支持最多128个激活灯光。
  • 同时只能支持8个投影阳光。
  • 到目前为止, 灯光只能有一种颜色, 不支持灯光节点组。

灯光探针

  • Eevee仅支持至多128个活动立方体反射贴图。
  • Eevee仅支持至多64个活动的体积辐射。
  • 在相机视野内,Eevee仅支持最多16个活动的反射平面。

间接光照明

  • Volumetrics don't receive light from Irradiance Volumes but do receive world's diffuse lighting.
  • Eevee does not support "specular to diffuse" light bounces nor "specular to specular" light bounces.
  • All specular lighting is turned off during baking.

Shadows

  • Shadows are not supported on light instances (instance objects, group instancing).
  • Eevee场景中仅支持最多128个激活灯光。
  • 同时只能支持8个投影阳光。

体素元素

  • 仅支持单次散射。
  • Volumetrics are rendered only for the camera "rays". They don't appear in reflections/refractions and probes.
  • 体素元素不接收体积辐射光但接收世界环境漫射照明。
  • 体素元素投影仅在其它体素元素上有效。它们不能在场景中实体物体上投影。
  • 体积阴影仅适用于视锥内的体积。
  • Volumetric lighting does not respect the lights shapes. They are treated as point lights.

Screen Space Effects

环境光遮蔽

  • Objects are treated as infinitely thick, producing overshadowing if the Distance is really large.

屏幕空间反射

  • 仅光泽BSDF支持屏幕空间反射。
  • The evaluated BSDF is currently arbitrarily chosen.
  • 屏幕空间反射将会反射透明物体和使用屏幕空间反射的物体,但是因为仅有单层深度缓冲没有准确的定位。

屏幕空间折射

  • 只有一个折射事件被正确建模。
  • Only opaque and alpha hashed materials can be refracted.

Subsurface Scattering

  • Only one BSSRDF can produce screen space subsurface scattering.
  • The evaluated BSSRDF is currently arbitrarily chosen.
  • A maximum of 254 different surfaces can use subsurface scattering.
  • Only scaling is adjustable per pixel. Individual RGB radii are adjustable in the socket default value.
  • Input radiance from each surfaces are not isolated during the blurring, leading to light leaking from surface to surface.

材质

Refractions
Refraction is faked by sampling the same reflection probe used by the Glossy BSDFs, but using the refracted view direction instead of the reflected view direction. Only the first refraction event is modeled correctly. An approximation of the second refraction event can be used for relatively thin objects using Refraction Depth. Using Screen Space refraction will refract what is visible in.
Bump Mapping

目前为止,置换贴图通过OpenGL衍生获得支持,对于每个2x2像素的块,它们是相同的。这意味着置换输出会显得像素化。建议使用法线贴图替代。

Tip

如果必要使用置换节点,渲染最终目标2倍大小然后降级到最终输出。

Volume Objects
体积着色器将影响对象的整个边界框。 必须使用着色器内的程序纹理调整形状。

着色器节点

  • All BSDF's are using approximations to achieve realtime performance so there will always be small differences between Cycles and Eevee.
  • 某些实用程序节点尚未与Eevee兼容(例如 天空贴图节点)。

See also

For a full list of unsupported nodes see Nodes Support.

内存管理

In Eevee, GPU Memory management is done by the GPU driver. In theory, only the needed textures and meshes (now referred as "the resources") for a single draw call (i.e. one object) needs to fit into the GPU memory.

如果场景非常大,驱动会交换切换物体进出来保证所有物体被正确渲染。

在实践中,使用太多的GPU内存会导致GPU驱动崩溃,冻结,或终止其它应用程序。所以请小心做出您的请求。

没有标准的方法来估计资源是否适合GPU内存,或者GPU是否能成功渲染它们。

CPU渲染

Being an rasterization engine, Eevee only uses the power of the GPU to render. There is no plan to support CPU (software) rendering as it would be very inefficient. CPU power is still needed to handle high scene complexity as the geometry must be prepared by the CPU before rendering each frame.

多GPU支持

There is currently no support for multiple GPU systems.

无窗渲染

目前Eevee不支持无窗渲染系统(例如没有显示管理器)。