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[BABE™]

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[Aliki_N]

Dazomatic,

I face a similar problem with reflections, especially for interior scenes. I have asked about why I see a reflection of the sky inside of a closed room, and I haven't got any convincing answer. If you make any surface inside of a room highly reflective, you get sky reflection instead of reflections of surrounding objects. ( See my animation pure architectural pleasure). There are reflections of the sky on the kitchen worktops. I was advised to use reflection conttrol effect. This just makes reflective surfaces more reflective as the camera passes. It does not eliminate the problem.

Alickn.

[Gilson Antunes]

I understand that the image that is projected from the hub of reflection is the view 360 ° of the camera location. ( video A)
As a star, a map is created in the first reflection, this map is used until the last frame. In video 2 and 3 stars is a map created by frame, as you can see in the video B and C.

VIDEO A


VIDEO B


VIDEO C

[Aliki_N]

Hi Gilson,

Thanks for your detailed explanation. Video "C" has correct reflections for both the exterior and interior scenes. Video "B" is the problem that I am facing, where the exterior reflection scene follows through into the interior scene. But how did you get Video "C" to reflect correctly with your animation starting from outside? There is something that I am missing here.

Regards,

Alickn

[Remko]

Cube maps are the easiest way to do reflection because it's basically just a texture map with some reflected coordinates. We simply can't do a ray trace for each frame. The trick for good reflections though is to pick the right reflection point. It should be at the center of the reflecting object. I hope we can provide multiple reflection points in the future so you can have multiple reflecting objects and tweak them properly. Pixar used quite a lot of cube map for all the reflections so you can see it works pretty well. For the movie Cars they used a ray tracer for the first time.

On flat surfaces the cube map does not work because it's really easy to spot they are all distant reflections and local reflections, like a guy standing on the floor for example looks weird. Luckily there is a second real-time reflection technique that only works on flat planes. It does an exact reflection of the scene in that plane and the image is used as reflection image. I hope we'll be able to add that to Lumion soon.

I've also seen a cool raytracing method which used a simple raytracer to look up coordinates and then render the reflection itself deferred. It's a lot faster than a full ray tracing solution. You can split the ray collision over multiple cores so the demo showed 50fps for ray traced reflections of a single bounce. The hard thing about ray tracing though is that you need to make a look-up table to quickly calculate intersections. One problem is that this look-up table becomes quite big for big scenes and a second problem is that it needs to be recreated for every frame because moving trees, moving cars and things like that.

There is some research in approximations where you simply render some shots of the scene and treat them like a point cloud. Each rendered pixel is a point in space and you can look them up for reflection and interpolate the missing gaps. Works awesome if you have enough info to reconstruct the reflection but looks horrible if there are big missing gaps. Luckily this will improve in the future as it becomes more easy to do things like this on the GPU. There is one common factor for all ray tracers though and that is the fact that they don't handle huge scenes really well.

[SEVERINO]

Hi Gilson,

Thanks for your detailed explanation. Video "C" has correct reflections for both the exterior and interior scenes. Video "B" is the problem that I am facing, where the exterior reflection scene follows through into the interior scene. But how did you get Video "C" to reflect correctly with your animation starting from outside? There is something that I am missing here.

Regards,

Alickn

Hello Antunes, Alickn think you want to know is how to get the reflection to show the option C.

I am working with a facade of a house that has a spherical glass and reflections that occur in Lumion do not like anything. That is why I wish we could provide a brief explanation of the steps to get the reflection of the option C.

Thank you very much and see you soon

[arch_bd]

I understand that the image that is projected from the hub of reflection is the view 360 ° of the camera location. ( video A)
As a star, a map is created in the first reflection, this map is used until the last frame. In video 2 and 3 stars is a map created by frame, as you can see in the video B and C.

Hi Antunes
it would be easier to present "video C" tutorial as a recording; which can be explained and understood more clearly the reflection control parameters used.
Thanks for cooperation is valuable for all

[Morten]

i still dont understand the reflection control how it works.........

The bottom line is that Lumion currently doesn't offer perfect raytraced reflections, only an approximation that works well in some situations and not so well in others. All reflective materials in your scene currently rely on a single cubemap texture (it's basically a 360 degree panorama rendered from a single point).

Here's how to use the Reflection control effect in your scene:
1) Reflection control -> All objects + Custom Position -> Set reflection point
2) Move the camera to the center of the soft drink cans and click on "Back".
3) If necessary, increase the "Reflection Minimum Range" to ensure that the cans themselves aren't reflected (as this will reveal that the reflections aren't raytraced).

If you were to add more reflective objects to the scene, they would use the same reflection point that you created in #2 above. The further away the new objects are from the reflection point that you created near the 2 cans, the less realistic the reflections on the new objects will look. What Remko is suggesting is to make it possible to create more than one 360 degree reflection texture, so that each reflective object has its own reflection texture.

TIP: Make sure that you render your movies in 2- or 3- star mode since reflections are not updated in 1-star mode.

[Morten]

I should also add that there is unfortunately a bug in Build 7 that prevents trees from showing up in reflective materials - obviously this needs to be fixed as soon as possible.

[Aliki_N]

This is very well explained Morten. Thanks, and thanks to all that had an input to this topic.

Alickn

[Gilson Antunes]

Hello
Morten has already completed the information ... to get the update of the reflected image you must render using option 2 or 3 stars.

[Morten]

Video C uses a dynamic reflection point, i.e. a 360 degree panorama as seen from the camera position. This tends to work reasonably well if you fly around a large scene with many different reflective objects:
Reflection control -> All objects + Camera Position

If you only have a close-up shot of a bottle or a reflective sphere in your video it would yield better results if you set a custom reflection position at the centre of the bottle/sphere:
Reflection control -> All objects + Custom Position -> Set reflection point

[Gilson Antunes]

Exactly.

-If you do not control use of reflection and surrender are using 2 or 3 stars, the reflected image is updated every frame.
-If you use the control of reflection, you can set a place to generate the image refleão that will be used throughout the video.

[Remko]

We want to change the behaviour of reflection in Lumion 2.0 because there are a lot of glitches. First of all we will add a blur function to reduce the amount of aliassing and second of all the position of the reflection cube will remain static by default. This should give nice results in 90% of the cases. With the refection control you can relocate the reflection or make it follow the camera.

[Gilson Antunes]

I think that every object should have an item "property" to adjust its attributes such as type of reflection, cast shadows, speed, textures, etc..