Let's Ray Trace

[TheKitchenAbode]

For those interested in exploring CA Ray Tracing Techniques.

 

From the CA sample gallery I downloaded the "Zero Sum Kitchen" plan. Other than reducing the width and height to 1200 X 618 I ran a Ray Trace as per CAs' settings. The scene took 1 hour and 54 minutes to reach a point were I could not detect any discernable graininess.

 

Here is the scene after 1 hour & 54 minutes, needed about 30 passes.

 

I reworked the lighting and altered some of the material properties. This ran in 1 minute & 44 seconds, only needed 5 passes.

 

Here it is at 4800 X 2472 if you wish to zoom in for closer examination. Took 28 minutes to run 6 passes.

 

The biggest problem with the CA plan are the point lights, in fact 18 of the 24 lights were points, even the ceiling recessed fixtures. They had Photon Mapping turned "ON" and even so the stainless steel rendered poorly. I changed all the lighting to spots and turned off the Photon Mapping, note that even with the Photon Mapping turned off the stainless steel rendered quite well, contrary to the common belief that one needs Photon Mapping turned on to render these metals.

 

That horrible orange colour cast has been eliminated, the scene now has an improved sense of depth, detail and colour balance. And it runs really fast.

[Electromen]

The 6" recessed lights in my plans are Spot by default.  I'm not sure why those ones are point.

[paulchoate]

Thanks Abode. Your tips have helped reduce my ray trace times dramatically. I cap them all at one hour and when I make the correct adjustments they look great...eventually I'll go from hours to minutes. 

[johnny]

Graham - that is a very nice job for Chief - very nice.

 

I think we all admit you aren't going to get such a complex scene in Chief where it appears to be a real photo, but that last version you have it about as close as it gets (from what i've seen).

[Dennis_Gavin]

Graham - what I don't like about your RT's is that the wall cabinets are much darker

compared to the Chief example.  My .02.

[TheKitchenAbode]

37 minutes ago, Dennis_Gavin said:

Graham - what I don't like about your RT's is that the wall cabinets are much darker

compared to the Chief example.  My .02.

 

That was a personal choice of mine, I purposely adjusted the cabinet finish, did the same for the freeform counter top section and the yellow wall colour. Other adjustments included reducing the reflection of the floor to expose more of the tile pattern, adjusted little things like the colour on the apples, flower vase material, pendant light material etc.

 

Once you get the Ray Trace time down to a few minutes it makes it easy to make all of these little adjustments as you do not have to wait very long to see the result. 

[TheKitchenAbode]

8 hours ago, johnny said:

Graham - that is a very nice job for Chief - very nice.

 

I think we all admit you aren't going to get such a complex scene in Chief where it appears to be a real photo, but that last version you have it about as close as it gets (from what i've seen).

 

Thanks Johnny, how far I can push this towards photo realism only time will tell. The Ray Trace program definitely lacks a number of features inherent in more dedicated rendering programs. One major issue is how Ray Trace deals with exterior sun light on interior scenes. Yes, it will create a bright patch say on the floor but it does not really take into account the overall effect this would have on the overall interior ambient light level and the lights overall direction & scattering effect. This will be one of the next things I will work on.

[Kbird1]

Thanks Graham , some more nice Renders , I will have to watch all the Chief RayTracing Videos i guess, as I still can't figure out what you are doing with the lighting to make it look so good, as just making the Point lights into Spots makes the Scene way too dark.  Can you elaborate on your lighting tricks or post your Zero Sum Plan for Others like me to look at? , thanks.

 

I think someone at Chief has seen your Point light advice as i see in the 5-12 Kitchen Plan (2017) all the Recessed lights are now Spots, unlike the Zero Sum Kitchen from 2013 and most are Points , it's also possible the materials like Stainless have been upgraded since 2013 too ,since CA was aware they didn't Render well...I made my own back then as I didn't even like them in Standard Views. 

 

 

[TheKitchenAbode]

Thanks Mick, there are really no tricks being used here, I'm just adjusting the main light properties such as intensity, cut off angle and drop rate and placed a few 3D type spot lights to provide some control over the overall ambient light level. If your scene is coming out dark then you have three ways to deal with that. One is to increase your lights intensity, reduce the drop rate or increase the cut off angle, the second is to up the max value under Ambient Occlusion and the final option is to use the image adjustment properties to adjust the intensity, contrast, softness, etc. It may actually require a combination of all three. You should work on one type of light at a time. Turn off everything except the ceiling recessed cans and adjust those for your desired effect, then turn on the next light type and adjust them. You need to do things one step at a time, otherwise there will be way too much happening and you will not be able to properly associate the cause and effect.

 

Will take a look at the 5-12 Kitchen plan to see what they have done. Hopefully it will run a lot faster and deliver a much better quality image versus the ones that I have tested.

[Kbird1]

Hi ,  yes,  I guess it is the light intensity, cut-off, drop off etc . and their combined use that I need to learn and don't seem to be picking up , that's why I was hoping to see an example plan.  Never been much good on "book theory" and all that dry reading doesn't seem to sink in , but seeing realworld examples and just trying stuff out seems too... so with your hints above I will play some more tonight.

 

thanks again.

 

[TheKitchenAbode]

6 minutes ago, Kbird1 said:

Hi ,  yes,  I guess it is the light intensity, cut-off, drop off etc . and their combined use that I need to learn and don't seem to be picking up , that's why I was hope to see an example plan.  Never been much good on "book theory" and all that dry reading doesn't seem to sink in , but seeing realworld examples and just trying stuff off seems too... so with you hints above I will play some more tonight.

 

thanks again.

 

 

Hi Mick, there is no reading involved as the stuff in the reference manual is not very comprehensive. This is a process of learning by doing. From everything I have done so far it becomes evident that this program attempts to follow the physics of light as it travels from a source and strikes a surface and is then reflected or scattered back depending upon the properties of the surface being struck. It can initially be fairly complex as you have light being emitted from many different sources, at varying intensities and angles all striking the materials and then intermixing and scattering throughout the room. As in nature too much light will washout a surface while too little light will not properly reveal the surface. One thing you can do is just look around your home and observe how the different light sources affect what you see, the depth of color and shadows. The exact same principles apply to Ray Tracing.

[Kbird1]

Oh good , it's not just me that thinks the Ref. Manual is not very comprehensive on these matters .

 

It might also partly explain why so many have issues with RayTracing and coming up with decent images without 6hr Raytraces .... it's why I am so interested in your techniques , they look good and are done in a decent time frame.....be a bit different if you could run 2 copies of CA and have one computer Raytracing while you worked on another .... personally I'd rather not have to learn (or buy) Thea Render or one of those other programs to do that , when CA is capable enough once you "figure it out" to produce nice RT's like yours.

[Renerabbitt]

6 hours ago, TheKitchenAbode said:

Ambient Occlusion

Graham as always, great input and posts, and nice work..hard work..kudos, gave you a thumbs up.

Ambient Occlusion is a major player in raytraces, it provides a host of fixes to 3d objects and how they react to light sources while maintaining the integrity of the model. Even if a scene is blown out and overexposed, ambient occlusion can save the shadows.

I've attached a clay render showing ambient occlusion at a low setting with no lights in the scene

vs ambient occlusion's minimums turned up.

You can see with ambient occlusion turned up you can produce a well-lit daylight scene without the need for point lights. The main benefit of point lights is to produce the metal effect in CA as the ray trace engine needs a direct light source to mimic the anisotropic effect of the metal

Additionally, it's a good idea to set color to your lighting so you can see what it is doing as you adjust it.

Graham, it looks like you have caustics and photon mapping turned off as well soft shadows turned off on all lights...I'd be curious to see what kind've speeds and realism you can work out with your methods with some of the better computational methods turned on.... You've proven the inverse works well.

A note to everyone, you can go into the 3d/3d view defaults and turn up interior ambient which will automatically set interior ambient in raytrace if you plan on eliminating lights.

Photon mapping and caustics need to find a light source, a good LARGE light source, but too many lights and the scene will be complicated. In a scene where you want to setup photon mapping and use as few lights as possible but still have the brushed metal its best to place a light opposite your camera angle...the same way you know a driver can see you if you can see his eyes in the sideview mirror.

Also white lights set to color mapping at 255,255,255 are harder to compute using photon mapping, set lighting to 230,230,230.

I think I remember a user named Jintu being pretty stellar with tricking CA.

 

[Kbird1]

Thanks Rene , more good info for me to pick away at this Ray Tracing thing with.

 

I have not seen Jintu (Chiefer) post much lately, not sure why, his RT's were/are excellent.

 

.

[TheKitchenAbode]

Rene - Some very good insight concerning those speckles and how Ambient Occlusion can be utilized to help counter this issue. I was in the process of preparing some thoughts and examples on this issue. Concerning this, my focus has been to first understand why these speckles occur in the first place so an effective strategy can be developed to avoid them to begin with. What I have been able to deduce so far is that these occur when there is an extreme difference between the exterior light level and the interior, typically a very bright exterior and poorly (low) lit interior. One of the deficiencies in Ray Trace is that it does not take fully into account the effect of the direct sun on interior ambient light levels. In nature as the exterior light levels increase the entire interior of a home would also increase as a result of direct and scattered light entering through the windows. In Ray Trace it only takes into account the direct light portion of the sun. Without using some special techniques the best way to avoid these speckles is to adjust the sun level down and use your interior lights and/or 3D lights to adjust the interior ambient accordingly. Just a warning, always make sure to have a roof on your house, otherwise this anomaly will be magnified. For environmental light you really need to have a foundation with a floor or you will encounter similar issues.

[TheKitchenAbode]

Here is the Zero Sum Kitchen after making some further adjustments. For this I turned on Photon Mapping and adjusted my lights accordingly.

 

The original CA rendering.

 

My previous render with Photon Mapping turned off.

 

My latest with Photon Mapping turned on.

 

You can see the effect of having photon mapping turned on. Please keep in mind that the light settings used in the non photon mapped scene must be adjusted as photon mapping treats the light differently. In most cases the light intensity must be reduced and sometimes by a considerable amount. For example, the under counter lights in the non photon mapped scene are at 60% intensity, in the photon mapped scene they are 7% intensity. The of amount adjustment will vary dependent upon the type of light and it's proximity to surfaces and the properties of those surfaces.

 

When photon mapping is not used light from it's source strikes a surface and then it bounces directly to the camera. When photon mapping is used the light will continue to bounce off surfaces 4 more times before reaching the camera. If you flip between the two pics you can see that darker regions in the non photon mapped scene are now brighter after photon mapping, watch the change on the espresso machine(left main counter top) and you will see that much more detail has been revealed as it is now receiving additional indirect light bouncing off of other materials. Conversely shadow strength has reduced as this additional indirect light reduces/dilutes their effect. 

[Renerabbitt]

34 minutes ago, TheKitchenAbode said:

 

 

When photon mapping is not used light from it's source strikes a surface and then it bounces directly to the camera. When photon mapping is used the light will continue to bounce off surfaces 4 more times before reaching the camera. If you flip between the two pics you can see that darker regions in the non photon mapped scene are now brighter after photon mapping, watch the change on the espresso machine(left main counter top) and you will see that much more detail has been revealed as it is now receiving additional indirect light bouncing off of other materials. Conversely shadow strength has reduced as this additional indirect light reduces/dilutes their effect. 

with photon mapping on you should be able to turn down "ambient occlusion maximum" in raytrace settings instead of adjusting your light parameters

[TheKitchenAbode]

Just now, Renerabbitt said:

with photon mapping on you should be able to turn down "ambient occlusion maximum" in raytrace settings instead of adjusting your light parameters

Yes, that is also an option. The only issue is that it will effect all lighting the same, it has a global effect. In my example not all of the lights needed to adjusted by the same amount as say my under cabinet lights.

[Chiefer]

On 7/7/2017 at 4:02 PM, Kbird1 said:

 

 

I have not seen Jintu (Chiefer) post much lately, not sure why, his RT's were/are excellent.

 

.

2

Present sir! following this thread

[TheKitchenAbode]

Image Properties

 

The Ray Trace Image Properties(top left little slider in ray trace window) is a very important tool. It allows one to make a number of image adjustments while your ray trace is running and after completion. This tool will have a significant impact on the look of your scene and depending upon the settings it will determine how you interpret your lighting and material when making changes & adjustments.

 

After lights are placed a ray trace is run to see how it looks. The look will be significantly affected by the light settings and the image properties settings. If the scene is not to your liking then is it the light settings or the image properties settings or a combination of both? The image properties DBX has 7 adjustment sliders and the Use Tone Mapping option, how these are set can make or break your scene. In fact improper settings can make it virtually impossible for one to generate a decent scene. These settings must be established to begin with and should remain fixed during the light & material adjustment process and then only adjusted once lights and materials have been properly set and balanced.

 

There are default settings for these and one would assume that they should be used, this however may not be the case. Here's what I got after placing my lights and running my ray trace at the default image properties settings.

 

 

Not so great, it's washed out, my whites are grey looking and everything looks soft. If I was not conscious of the image property controls I would go back and start adjusting lights and material properties, maybe adjust the ambient occlusion, run more passes, etc. Now that may work, but every time you make one of those adjustments you will need to run another ray trace and that's more time spent. Since the image property settings can be adjusted after a ray trace then maybe I should see first if something there might help. The big benefit is that these changes are instant(live), no need to run another trace. So lets see what I got.

 

 

The scene has changed significantly, it's crisper, has improved dynamic range, colors are more vibrant and whites are whiter. Depending upon your needs then maybe that's all you needed to do to have a satisfactory rending. Even if it was not fully complete, which  do you think would be a better one to start from?

 

As demonstrated above, the image properties will determine how your lighting and materials will appear. You need to make sure that the image properties are reasonably good, otherwise you will be adjusting lights and materials under less than ideal conditions. Just my opinion, but the default image property settings are not conducive to good results. These are my typical settings,

 

Tone Mapping "ON"

Contrast 35%

Intensity 35%

Softness 4%

Color Correction 0%

 

Brightness 48%

Contrast 70%

Saturation 50%

 

I leave these alone while adjusting lighting and materials. Once I have things looking satisfactory under these image property settings I can then go back and tweak the image property settings a bit to finish off the scene. I have also found when I adjust lights and materials based on these image property settings that when I tweak the final image via the image property settings there is lots of adjustment tolerance before the pic will degrade due to over application.

 

For those curious about the posted scenes lighting, it has been done to look as if all the lighting is from the exterior on a nice bright sunny day. None of the interior fixtures are active. The Sun Intensity is 50, Ambient Occlusion Min=1, Max=9.5, Photon Mapping "On", Focal Blur = f8.0. I never use "Use Camera View Settings" and Environment Light is "Disabled" as is Caustics.

 

Here's one more of the same scene, Just used the image property settings to tone it down a bit.

[Kbird1]

16 hours ago, Chiefer said:

Present sir! following this thread

 

Sorry Jintu , just hadn't seen you post in a while , and I have always followed your RT advice in the Past ,

so I was hoping you'd "drop by" this thread and post some tips for us mere mortals to use

[Kbird1]

Hi, Thanks Graham , that is great info , I am still playing with drop off Rates etc but a couple of questions from your last post...

 

Direct Lighting Intensity (Sun?)  is 50.0   not 5.0 correct ?

 

and

 

If you don't use "Camera Settings from View" ,  what colour light are you using instead ?  230.230.230  per Rene's suggested numbers or pure white ? (255.255.255)

 

and

 

From being a Photography Enthusiast for many years I know F8.0 is a pretty shallow depth of field , does it work the same way in CA X9?   as I am not usually carefully placing the focal point when I draw out a Camera View.

 

and

 

Do you enable Bloom ? if so what Radius and weight do you use?

 

 

Oh...much nicer ....just ran a RT On the Zero Sum Kitchen I've been fiddling with as I have time,  using your settings above as I typed this reply but I left my lighting as it was (on),  10 passes ran in 5mins on my old machine which is pretty good considering it is an older i7-950 @3.6 .     ( I'm upgrading my Newer X99 CAD machine with a 980ti and reinstalling Win10 Tonight as well.) 

Only thing I'm not liking is the puck lights , I think it is, in the cabinets either side of the rangehood , they look like they are both 12" dia. Dome lights hanging down , since I guess I missed them when playing with the light Data ?  or I need to Turn Off ALL interior lights as you suggested?

 

Thanks Mick.

 

.

[TheKitchenAbode]

Hi Mick, in the sample I posted under Image Properties the direct sun was set at 50. I usually have this set between 5 to 10 but for this one I wanted it at it's max. My lights are almost always at 255,255,255. You can of coarse change this if you prefer a warmer light. Not sure how accurate the f factor is, don't normally use this but will be doing some test runs in the future to see exactly what it can do. Never use the bloom, I think if you want this kind of effect you would be better off using a photo editing program.

 

Just to clarify on not using the "Use Camera View Settings", the main reason is that I may at times change this for my regular camera views, just don't want this to automatically effect my Ray Traces. 

[Kbird1]

1 hour ago, TheKitchenAbode said:

Hi Mick, in the sample I posted under Image Properties the direct sun was set at 50. I usually have this set between 5 to 10 but for this one I wanted it at it's max. My lights are almost always at 255,255,255. You can of coarse change this if you prefer a warmer light. Not sure how accurate the f factor is, don't normally use this but will be doing some test runs in the future to see exactly what it can do. Never use the bloom, I think if you want this kind of effect you would be better off using a photo editing program.

 

Just to clarify on not using the "Use Camera View Settings", the main reason is that I may at times change this for my regular camera views, just don't want this to automatically effect my Ray Traces. 

 

Thanks Graham , those settings under your the Images Properties Post work really well when all lights are off , the Bonus of course is that you don't need to be an expert in CA Lighting Techniques and anyone (I) can still get good results in about 5mins .  this is one I ran earlier , trying settings though I used Rene's 230,230,230 , and I had previously played with some of the material properties , like emmisiveness etc.  Bloom was not on as for me, it makes the Image too soft for my liking.  If you have any thoughts on improving the image after looking at it please let me know. Thanks again for your Help.

 

M.

 

 

[Renerabbitt]

3 hours ago, Kbird1 said:

 

Def lookin good Mick

 

I was playing around with some new textures I've been making...4 min rough render for giggles