Lighting

[barkest]

For a long time now lighting has not worked in VW. I think I posted a long-time ago about this subject so maybe it has moved on and I a missing something and if so then please let me know.

I use lumens as the value and typically something around 650 lumens as a point light in the room. As interior designers it is important to know the lumen value and what it is going to result in so a percentage strength is irrelevant.

In order to make the 650 lumens work, after a lot of trial and error some time ago, I found that a Dimmer value of 1250 meant that the lumen value gives me a good approximation of what things will look like. This works for point lights and area lights. For spot lights the lumen value works fine without having to adjust the dimmer value.

In 2015 the situation got worse as an Open-GL render starting working, I assume it was fixed. This puts me in a situation where I adjust the dimmer to 1250 and that works fine with fast/final render but gives me a complete white out with Open-GL. See the two attachments. One is Open-GL without the dimmer adjustment and the other is final render with the adjustment. Both look more-or-less the same.

All-in-all its a well done for finally fixing this issue but it has only been fixed in Open-GL which has made things much worse because at least there was a consistency before with the renders whereas now there is much more confusion.

I would be grateful is others could let me know how they deal with this issue?

thanks

[RickR]

I have answered similar comments, perhaps one of yours, by pointing out that VW is not a physics based lighting program. It does not include light from reflections. It has very little connection to what happens in the human eye. True lighting analysis software is very different.

My wish is that they would use a different word for the lamp source. A Lumen is of a standard recognized world wide and what VW does has no bearing on what a real lumen. I think it creates expectations that can not be met.

I build my model and do all my construction drawings in VW. The model goes into Relux, AGI32, Dialux or other scientifically vetted and calibrated analysis program.

[barkest]

Thanks Rick but it holds that at present there is more inconsistency than ever now that openGL appears to have been fixed. At the very least remove the inconsistency. I teach interior design and from a students perspective they are dealing in visualisations so it has to 'look like' what the client is going to get rather than being technically perfect. We are selling an idea.

The current setup works fine for us but needs fixing as it is in a very confused state.

thanks for the reply

[AlanW]

Hi,

You mentioned that "It does not include light from reflections".

The attached image has 1 spotlight shining up at a surface that is reflective and you can see the diffuse shadow of the centre object on the surface below. This light is reflected down providing the shadow.

This light has realistic falloff.

Open for discussion as to whether this works or not.

[Kevin McAllister]

The realistic lighting may get a lot better in a coming version. The new versions of the C4D rendering engine work a lot more like RickR is describing. If the one VW is using gets updated to one of these newer versions that should translate across to VW.

I don't even think the current version VW uses supports linear workflow. It would be nice to access the physical renderer, the reflectance shader and various other improvements.

KM

[RickR]

My point is the difference between estimating and calculating. It's a fine point, but critical to getting results that will be close to the final product.

I suggest reading a bit on calculating lighting based on physics.

http://en.wikipedia.org/wiki/Path_tracing

http://en.wikipedia.org/wiki/Ray_tracing_%28graphics%29

http://en.wikipedia.org/wiki/Radiance_%28software%29 (the basis of most architectural lighting calculations)