BlendLuxCore FAQ

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Frequently Asked Questions

I can not enable the BlendLuxCore addon, it shows errors

If you have installed the OpenCL version of BlendLuxCore, try updating your graphics driver.

For Windows users:

If this does not solve the problem, browse the installation issues in the bug tracker to check if your error message was already reported. If it was not reported yet, open a new issue and copy the error message from the Blender console (on Windows, click Window -> Toggle System Console in Blender's menu. On Linux, start Blender from a terminal and try to enable the addon, then copy the error message from the terminal).

See the installation page for information on how to install, update and remove the BlendLuxCore addon.

Why is my HDRI environment black and not showing up?

You probably have other very bright light sources in the scene, for example a sun or a sky lamp.

Solution: raise the gain value of the area or HDRI light source that is black. The gain value might need to be very high, e.g. 100000.

Why is my area lamp black?

See #"Why is my HDRI environment black and not showing up?"

When I change the brightness of my lamp, nothing happens

You are probably using an automatic tonemapper which adjusts itself to the changed brightness, making it seem like the brightness did not change.

Solution: Use a non-automatic tonemapper (camera settings -> ImagePipeline).

When I make one of my lights brighter, all the other lights get darker (or vice versa)

Similar to #"When I change the brightness of my lamp, nothing happens".
You are using an automatic tonemapper which tries to keep the image at the same brightness, making it seem like the brightness of the lamps changed.

Solution: Use a non-automatic tonemapper (camera settings -> ImagePipeline).

A material/object appears to be flickering when I move the camera and shows artifacts in final render

This effect is called Z-fighting and is usually caused by mesh faces being exactly on top of each other, e.g. two planes on the same world coordinates.


  • Check if there are two objects on top of each other, e.g. because you duplicated the object, cancelled the transform and forgot about it.
  • Check if the mesh has duplicate faces. Enter edit mode and use the Remove Doubles button in the Tools panel, which might solve the problem in some cases.

Duplicate faces are often caused by extruding, cancelling the transform and forgetting about it.

There are dark triangular artifacts on my model, and I already checked for duplicate faces

Floating point numbers have a limited precision. When objects are very large (kilometers) or very small (micrometers), these precision issues become visible.


  • If the object has a "normal" size (something like 1 cm to 1 km), but was scaled up/down by a huge amount, try to apply the scale (Ctrl+A -> Scale). For example, this often happens with imported CAD models.
  • If applying the scale did not help and your object has to be very small or large, consider to bring it into the normal scale mentioned above, and pretend that it has a larger/smaller size. For example, if you make a model of the solar system, you will just have to make the earth something like 12.742 m in diameter, and pretend that 1 m of your model is equal to 10^6 m.
  • If both options above are not usable in your case, you can raise the minimum epsilon that LuxCore uses. This setting can be found in the scene properties, Units panel, after clicking "Advanced LuxCore Settings". By default, the minimum epsilon is 0.00001. Try to raise it to 0.0001 (multiply by 10) for a start and see if the artifacts disappear. Do not set this value higher than necessary, because it will cause all sorts of hard-to-track problems. Be especially careful if you are rendering a scene with volumes.

An object that I set to "smooth shading" looks like it is shaded flat in shadow penumbras

This artifact is called "terminator problem".

Solution: Unfortunately there is no real solution. You can only try to mitigate the effect by subdividing the geometry further and/or increase the size of the light source that is causing the problem.

How do I setup liquid in a glass container correctly?

This forum thread shows an example:

Getting Help

If none of the above entries helped to solve your problem, consider asking in the user support forum or filing a bug report.