V15 Indoor render to verify type and quantity of lights - feasable?

[dBminus]

Hi All,

I'm an amature TFP user.  We designed our retirement home with it and I'm always amazed at what it can do.  I'm at the point where we're trying to determine our recessed can lighting in a room with high vaulted ceilings and dormers that let light in.  Now I'm experimenting with the advanced render schemes and interior lighting.  I'd have to say that the rendering outcomes have got me confused.

Here is what I think I've learned from reading this forum:
V15 indoor lighting will turn off if sunlight comes in a window  (previous versions one had to scale down indoor lighting, now its the opposite?)
Using different wattages or light types in different fixtures causes unpreditable light rendering
Use radiosity setting of 3 or higher (using 4 - with anti-aliasing of 4)

For my model, I turned off daylight, set time of day to night, used nighttime sky graphics....
I inserted a bunch of recessed cans in the vaulted ceiling.  Got the 'halo' light bloom on the ceiling.  Read where Allan suggested to lower the 'bulb' (red magic light block viewable in the 'lights' tab of the interior light property dialog).  That helps...  

I ran an experiment that has me confused.  I created a simple house model with an interior 6' cube made of drywall - no windows.  I put a recessed can in the ceiling and it rendered fine with no halo.  Being very simple, the convergence factor went from 1 to .1 in much less than the 1000 default steps allowed.  In the big model, the convergence had only reached .45 after 1000 steps.  Increasing the steps to 10000, I watched the render until step ~ 6000 where convergence was .2  The halos were still there.  I don't know why my test case works fine but the complex model acts different.  

Seems like as I add more lights, the 'auto iris' of the camera keeps the exposure constant.  I don't have a lot of confidnce that I need 10 recessed cans or 50.  Am I expecting too much science from this process?  Rendering an indoor scene seems like an art form and maybe thats all I should expect.... just tweek until its a pretty picture, but don't add up the types and wattages of the lights to make it that way...

Any insight you render experts have would be appreciated.  I've learned a lot of behaviors of various 'bulbs' in my 6' box.  Did you know putting an 'up light flood' bulb in a recessed light makes a spot light on the ceiling   Any clues as to how to turn the red cube around?  Turning the fixture doesn't effect the bulb, apparently....

Well, Thanks in advance... and btw, the scroll box for typing a long message seems to hide the bottom text between keystrokes... at least on my machine...  Guess I've typed too long a message...

[Jack Zimmer]

Hi Dave,
Lighting is an art form , or should I say rendering in general which takes into account both light and materials and camera angle. In addition I am not sure any program is accurate enough to actually determine light types / location and wattage.

You can get a nice rendering for viewing a scene but the rules you mentioned help, like increasing wattage with Sun on.

Because of the variables it is hard to comment without seeing and discussing your layout and materials. I in fact plan on a 'book' series of videos on the subject. But all that being said, I do have a method I have developed that is pretty much fool proof and gets good images. But even that has it own set of rules that while simple are too involved to get into here.

Jack

[dBminus]

Hi Jack,

Thanks for your insights.  I'm still unable to get the same rendered results using the recessed cans in a test 6' cube verses my house model.  In the test cube, I can put the can inside a sealed 'tube' and no light comes out.  In the complex model, light escapes the sealed 'tube' and causes a halo on the ceiling.  The two models just don't render the recessed can lights the same.  In the simple 'box' house, the recessed can works fine and it seems to behave correctly if I contain it inside a 'metal tube'.  Not so in the complex house.  The 'polygon' count for the simple box is always in the hundreds.  For the house, its usually around 99,000.  I guess thats a much tougher solution.

Edit update:  I ran a file:repair project and using the 'stock' 4" recessed cans in the complex model ceiling, they all rendered correctly (no halo on the ceiling!)  So I'm guessing that somewhere in my edits, I created a bunch of junk that the repair fixed.  The lights seem to be working fine now.... but I guess I should'nt count my watts as a basis for the real house lighting....

Amazing what this program can do

Thanks for your help,
Dave

[dBminus]

Hi All,
I discovered that my recessed can lights can 'break' based on whether or not I turn on the dining room light, or if it uses a recessed type bulb, or a chandelier type bulb.  Strange.  Do I have to model each light fixture with a recessed bulb for the rendering to work correctly?

Here are a few renders.  They are all adv renders setting 5 with anti-alias at 4.  They all run to the default # of steps (1500), but the convergence varies between .35 and .45 (does that mean that ~40% of the light rays are unaccounted for when it hits the step # stop?)

The pics are from a family room towards a free standing kitchen.  At night, no daylight.  #1 is with dining room light off (dining room is opening to right left of kitchen)   #2 is with dining room light on - set with 4 75w recessed type incand. type bulbs.  #3 is with dining room fixture with original 100w chandelier type bulb.  With #1, it looks like the left table lamp is hot along with the right ceiling recess can.  With the dining room 4 75W incand on, pic #2 looks like I dimmed the lights in the family room and the lower right kitchen cab light went out (but it was on).  Pic #3, just changing the 4 75w bulbs to 1 100w chandelier incand broke the ceiling recessed cans.  The kitchen cab lower right is still out.  Theres a strange light on the outside of the windows to the right lighting up the siding, but there is no light outside.  All 3 pics have exactly the same lighting in the family room and kitchen - which is what is in the viewport.  So, I can get 3 quite different renders of the same space by changing the dining room light properties...  oh well.  Its an art form...

[Allan Chesney]

Hi Dave,

Welcome to the forum and welcome to the joys of rendering.

As was mentioned before it is a bit of an art form but with a little experimenting some excellent results are possible. You appear to have done an excellent job with the model and even each of the renderings are good in their own way.

I discovered that my recessed can lights can 'break' based on whether or not I turn on the dining room light, or if it uses a recessed type bulb, or a chandelier type bulb.

Yes, as you have found, one light can 'break' another.  I don't quite understand the logic of that but it does happen. It is obviously baffling the programmers a but too!

Do I have to model each light fixture with a recessed bulb for the rendering to work correctly?

I have found that I have the best and most consistant results if I only use the same light bulb and the same wattage in all fittings. This way usually they all stay on.  If I need a down light I just lower the bulb to give that effect and if I need a light dimmer than the others I just colour the bulb, usually with a shade of grey but occasionally with a colour for special effect.  I have got away with different wattages and bulb types but with a lot of experimenting and often I do not have the time - so I make them all the same.

All the best with your renderings. When you get close to what you want it would be nice to see some examples in the Gallery!

Allan

[dBminus]

Hi Allan,

Thanks for the welcome, and thanks for your help.  I don't think I would have gotten this far without reading many of your posts and your tips and tricks with easy to follow steps!

I took your advise and changed all the bulbs to one type.  That solved the dining room fixture breaking the recessed cans problem.  Unfortunately, I chose the recessed can bulb as my standard, then ran into problems scattering the light on the ceiling with other hanging fixtures.  I ended up sneaking a few pendant type bulbs in the mix, and I'd keep breaking the can lights as I added more and more fixtures     I think I'll go back and use a better general purpose bulb and lower them from the cans per your suggestion.

By the way, do you know of any way to rotate a bulb?   I've tried rotating the fixture, but the bulb doesn't seem to follow.  Virtual reality has its ways

Thanks again, and I'll post some renders to to gallery once I'm finished.  The forum sure has a nice collection.  I just hope mine turn out half as good as the one's I've seen you do

Dave

[Allan Chesney]

Hi Dave,

I'm glad that solved the problem - I have found using all the same bulb is the quickest solution.

By the way, do you know of any way to rotate a bulb?   I've tried rotating the fixture, but the bulb doesn't seem to follow.

By "rotate the bulb" I assume you mean where you have multiple ones in one fitting?  The only way to do it is by changing the XYZ settings on the bulb using positive and negative figures to move the bulb backwards and forwards, left or right. The distances entered are in relation to the centreline of the fitting itself (which basically is irrelevent - it is just for appearances).  You can actully use the bulbs without a fitting (almost) - just set it to extra tiny or make it all transparent.  You can then put some general light where you want it for effect or to brighten dark corners without seeing the fitting.

Looking forward to seeing your final renders!

Allan

[Doug.S]

While I cannot be completely confident, your walls may contribute to your lighting issues...maybe.

What I could see in the rendered images is uneven light on the walls.....with exact lines of change...which seems like some walls are made of pieces and they are not aligned exactly.

Look near can lights at far left and far right and see a light brightness change...light to dark...not from the bulb light but a vertical line on the walls.

Sometimes a "file fix/auto repair" will fix walls but not always. So the manual solution is to zoom in as close as you can to every wall joint and check that the walls are aligned exactly to one another.

If you cannot see what I'm talking about, let me know and I'll mark up a rendered image. If you attach a .bld file I can mark and render to show it even more dramatically and also see how you constructed the various walls.  The "best" is to use only continuous walls and cut out openings rather than build openings by using multiple wall pieces.

Doug


PS  Also since your ceilings seem to be canted (not horizontal level) the light fixtures need to be carefully aligned with the ceiling to prevent light leakage....as they may not align or be exactly flush as is typically automatic with a conventional flat ceiling at 8' and auto installed lights for height to match ceiling height.

Again, zoom in as much as possible at the light fixture to ceiling interface to verify the correct alignment to each other as well as the light bulb red cube to the fixture.

[dBminus]

Hi All,
Allan, by rotate the bulb, I was meaning can one take a 'up light flood' bulb and rotate it 180 deg and make it a 'down light flood'.  In my 6' test cube, I put an up light flood.  Saw the spot light on the ceiling.  Then I rotated the flood 180deg so it was pointing to the floor, and the bulb still cast the same spot on the ceiing  Seems like the photons from these bulbs go right through the fixtures as well.   Just curious if the actual 'bulb' could be rotated in the X,Y,Z axis.

Hi Doug,  You've got a good eye.  The uneven light on the walls bugged me too.  I double checked the 'paint' for consistency.  Checked the wall for continuity and as best I can tell, it is one piece.  The shiny strip seems to correspond exactly with wall protrusions that go into other rooms.   The shiny break on the right side is where two walls meet from from different locations, but I don't know why one would reflect more than the other.  I had tried to use one wall originally, but I could not get my opening to be flush on the farthest wall, and I always had issues selecting the dormer windows in plan view, so I put the dormer wall/window on another location.   I attached just the wall view of the left side fyi.  If you'd want to look at the whole model, you're welcome to... I'd just warn you first that its ~ 13mb.  Its got a few out buildings and other stuff helping us visualize the final landscape...  Here is a pic standing back from the house...  Thanks for your help and suggestions.
Dave

[Allan Chesney]

Hi Dave and Doug,

I noticed the different shades of render on the wall and assumed (correctly it seems) that there are walls joining this wall on the other side of it. Unfortunately this does happen, even if it starts as a continuous wall - as soon as walls join to it on the other side you can get a different effect. (see my test image below - purposely set up the same way). The only way I have found to overcome this is to temporarily drag the attached walls away form the wall in question (by just a mm or fraction of an inch). As long as long as the other walls do not actually attach, the wall on the opposite side will be OK.  Still looking for a cause and fix on this one.

Re rotating the direction of a light:  If you want to use the same bulb throughout the model to overcome render issues, all you need to do is move the bulb up or down to get the effect you want from each light.  

If you want some general light on the ceiling (but not a bright flare) then place the bulb say a third of the way between floor and ceilling. To make it a down light add another bulb and move the second bulb closer to the floor to give a 'flare' on the floor or table.

For a twin flood light (as for example used in sensor security lights) use two bulbs, move one to the left and the other to the right so it mimics the effect of the twin flood lights onto adjacent walls for example (lower them if you want to give the twin light effect on the ground).

If you use these ideas any light fitting can be an up, down or sideways light and all use the same bulb.

The outside view looks good - it would be nice to see it rendered! Basic render is usually fine for oustide, especially of 'distant' views. If close up to verandahs etc then Advanced may be better.

Allan

[dBminus]

Hi Allan, Doug,
Thanks for the wall shine explaination.  I'll try pulling the other walls back a tad so the final renders don't have that strip down the wall.

Sounds like I need a redo of my lighting fixtures using a general purpose bulb.  I'll get this right sooner or later   With all recessed can bulbs, the lighting never seemed to break, but I couldn't get general light on the ceiling either...

TFP has been very helpful working with the builder.  I keep updating the model to reflect the actual builder drawings and then I show him images of the deck or interior where I have questions.  His drawing is a 2D acad model and sometimes its hard for me or my wife to visualize what he's thinking.  TFP is a great go-between for 'getting us on the same page'.

Once again, Thanks much for the advise and tips.  The project is shaping up!  (must say the virtual house is much farther along than the real one though...)

Dave

[Allan Chesney]

Hi Dave,

Just a thought if you were going to change all your lights: You only need to change one recessed light for example and save it to the Catalogue (or Add/Edit one in the Catalogue). You can then right click one in the model and choose Select All Similar, then right click and choose Replace. This will replace all the ones in the model with the new one with adjsted bulbs .

Yes TFP is great for seeing how things will look and I agree, virtaul homes are much quicker!!

Allan

[dBminus]

Hi Allan,
I pulled the joining walls back from the left side wall and the light stripe is gone!  I was able to nudge those walls back to be right on the wall outline, but since they're no longer 'joined' the render came out fine.  Great tip,  Thanks.

Here is the adv render of that.  I still need to redo the lights.  I'll try your suggestion.  Should save a bunch of time.

Dave

[Allan Chesney]

Hi Dave,

The render looks really good and the model is excellent  You have obviously put a lot of work into it as it is quite a complex design.  Congratulations!!

Looking forwar to seeing further renders later!

Allan

[Doug.S]

Another tip for you....to save significant render time and sometimes "fixes" unknown problems...or allows you to render at higher qualities and the render time is not so bad.

Save the most current design as a "master" file for safe keeping.

Make 2 or more copies of it....for different rendering purposes...such as:

- use one file for outdoor renders....and delete anything indoors that would not be visible or contribute to the render lighting...only render outdoor views from this file

- similarly, for indoor views...delete all exterior extra bldgs and gut rooms not seen/used....should reduce render times and sometimes yields better renders as TFP no longer calc the extra objects/lights/etc.

The only down side other than extra files/disk space is if you make any important re-designs, you may need to repeat or update several files...maybe!