PBR VS Raytracing

[Kbird1]

3 hours ago, TheKitchenAbode said:

Global Illumination must be turned on in Preferences. Preferences, Render, under troubleshooting, turn on "use Global Illumination".

 

Good Point ...  it should never be Off if you are using PBR Views from what *Dermot or *Brian said a while back.

 

*CA Software Developers

[Designer1]

I started setting my first PBR up and took notes of all the advice on this thread.  Now the only thing that seems to be off is the sun...haha.  For some reason with global illumination on and everything else on I cant seem to find where to turn the sun on.  I have the sun angle and everything else on.  Basically it just has the same lighting 360 degrees around the house.  Im sure this is something stupid I have selected and its simple but because I haven't even done a raytrace in three years let alone PBR its confusing me.

 

Any ideas where the switch for the sun is?  Im trying to find humor in my mix up.

 

Thanks!

[Kbird1]

5 minutes ago, Designer1 said:

Any ideas where the switch for the sun is?  Im trying to find humor in my mix up

 

from a 3D camera............

[Designer1]

Thanks for the reply Mick!  I just got to this right now sorry for the delay.

 

I figured out how to get the shadows to work for the most part in PBR but don't know why the shadows aren't working for the trees?  The shadows work for the trees in raytrace but not PBR.... is there a secret lever Im suppose to pull to get these shadows to work for landscaping?? 

 

Im trying to use humor to keep myself in the game as Im learning this PBR thing...lol.

 

 

[robdyck]

4 hours ago, Designer1 said:

but don't know why the shadows aren't working for the trees? 

Plant images only produce shadows using raytrace. For shadows in PBR you'll need 3D plants, and you'll need to select carefully. Look carefully at the vector view of the 3D plants' leaves to get an idea of what the shadow will look like (big squares vs leaf shapes). Also, plant shadows in PBR are usually quite harsh and may need to be backlit in order to soften the shadow.

Keep in mind that the lighting used to produce a good pbr may be terrible in raytrace. If you're using both render types, I'd suggest using different cameras with different lighting scenes.

FWIW I never touch raytrace anymore...too time consuming. If I or my client need those top quality images, I've found it's cheaper to outsource.

[Chrisb222]

5 hours ago, Designer1 said:

The shadows work for the trees in raytrace but not PBR

 

You must be using the Core catalog 2-D plants. Those don't produce shadows in PBR, only the 3-D plants in Bonus catalogs do. See this post:

 

 

 

 

[TheKitchenAbode]

As mentioned, in PBR only the 3D plants will cast shadows and also as mentioned those shadows can be down right ugly. They are more like silhouettes than shadows, looks like they were cut out of a black piece of construction paper and pasted on the scene. You can dilute their strength by using an area light with shadows turned off, might need to reduce the suns intensity to get compensate for the extra area lights contribution. Another thing worth trying is to open up the cameras DBX and uncheck "Raytraced Shadows", in most cases the shadows will soften with less defined edges. Not 100% as depending on the sun angle and camera angle the shadow edges can look like a saw tooth. If you are going to change the existing 2D plants to 3D plants I would suggest doing one at a time to see if you like the effect, maybe not all need to be changed.

[Designer1]

Thanks everyone for the replies. 

 

Yikes...looks like Im going to have to use a combination of Raytrace and PBR.  This should be interesting.  Yeah Ill just stick with Raytracing for the exteriors then as it sounds not very favorable to use PBR for exteriors.  From other topics on PBR is sounds like interior renderings using PBR are as good if not better then raytracing... so I will have to see how that goes.  It seems from more experienced users on here that posted earlier that minor tweaking of the lights and sun are the only changes I might need to make as far as interior lighting goes. 

 

Cheers to the adventure of raytrace and PBR renderings coming up!

 

Thanks again for the replies and input!

[Designer1]

Does anyone know where the default raytrace options went?  I looked on X11 help resource but the directions there aren't accurate to how the program is set up???  Heres what Im talking about...

 

It works in 3d if you hit the raytrace camera button but where is it in defaults?

 

Thanks!

[Alaskan_Son]

1 hour ago, Designer1 said:

From other topics on PBR is sounds like interior renderings using PBR are as good if not better then raytracing.

They are faster, a little easier, and offer near instantaneous feedback.  They’re definitely not higher quality though.  They simply cannot depict lighting and shadows nearly as realistically as ray traces and there’s nothing even the most advanced user can do to fully remedy those limitations.  Control over said lighting and shadows is also a lot more limited in those PBRs.  There’s a lot that could be said on this topic, but the most glaring issues to me are the way PBRs basically handle lighting as an aggregate differential, the lack of effective soft shadows and ambient occlusion, the jumpy way it handles reflections depending on the camera angle, and it’s lack of proper reflective glass behavior.   
 

Now don’t get me wrong.  Ray traces have their issues too, and PBRs certainly have their strengths and can be a totally useful and effective tool.  I wouldn’t call them as good or better though.  

[Designer1]

Thanks Michael, I will keep all that in mind.  At least we have two different options to work with so hopefully I can find a use for both of them.

[Designer1]

Can anyone give me any lighting advice on how to lighten up the pitch black shadows under the island?  I was also looking at how the recessed lights don't lighten up the ceiling as well as they do in a raytrace either... so Im trying to experiment with different lighting to try and get this to look as realistic as possible.

 

This is my first PBR interior rendering.  I can see the benefits and the challenges that everyone was talking about earlier and it does take some getting use to. 

[robdyck]

2 hours ago, Designer1 said:

Can anyone give me any lighting advice on how to lighten up the pitch black shadows under the island?  I was also looking at how the recessed lights don't lighten up the ceiling as well as they do in a raytrace either... so Im trying to experiment with different lighting to try and get this to look as realistic as possible.

 

This is my first PBR interior rendering.  I can see the benefits and the challenges that everyone was talking about earlier and it does take some getting use to. 

 

Use a lighting set for each camera. I save my lighting sets with names that correspond to the camera they are to be used for.

Experiment with a very low sunlight setting (1000). You can also change its color to affect the hue of the scene.

Adjust the PBR camera technique settings.

Perhaps don't have shadows on for each interior light. Again, experiment. 

For the island, you could add rope lighting under the countertop, or just an 'added light' (think flashlight) to cast more light into that area. 

 

Playing with those should get you closer...

 

[TheKitchenAbode]

5 hours ago, Designer1 said:

Can anyone give me any lighting advice on how to lighten up the pitch black shadows under the island?  I was also looking at how the recessed lights don't lighten up the ceiling as well as they do in a raytrace either... so Im trying to experiment with different lighting to try and get this to look as realistic as possible.

 

This is my first PBR interior rendering.  I can see the benefits and the challenges that everyone was talking about earlier and it does take some getting use to. 

 

From my experience I approach this in stages, first to tackle the sun, then the most dominant light fixture(s), followed by the next lights. Once everything looks half decent then I work on tweaking the materials. I will just address the sun in this posting.

 

Starting with the sun. Have at least one light fixture in the scene(room), turn it off. You need this to override CA placing a generic light source in the scene. Open up your PBR Camera, ignore the fact that it will probably look terrible. Open up the PBR DBX and set Camera Exposure to 1(max) and Brightness to 100%. Again ignore how bad it may look. Now open up the Sun DBX, if the scene is way too bright then reduce the sun intensity. If you have a background then the sun intensity is going to be determined by how you wish the background to appear through the windows, ignore the interior.

 

Once the background is to your liking then adjust the suns angle to get your desired direct light effect through the window(s). It's most likely at this point that your background will look decent and also the direct light patch, but the room is likely to be very dark. The first urge is going to be to turn on interior light fixtures to brighten up the interior, don't do that. If you think a bit about how the current PBR scene looks and how it should look in real life given the outdoor brightness and level of glazing you have to conclude that somethings not correct. In real life the interior should be much brighter and this should be as a result of only the sun. There are two components to the sun, direct light and indirect light, the bright(er) spot on your floor from the window is the direct light component, what's not showing properly is the indirect light. Unfortunately in CA there is no direct way to adjust the ratio of the suns direct and indirect component, it's fixed. Yes, you could just crank up the sun but this will then overexpose the background, make the direct light from the window overblown and introduce a strong color cast from the background into the interior, the results can be outright ugly.

 

There must be another solution and fortunately there is and it's actually very simple, "Materials Emissive". This materials property imparts to a material the ability to act like a light source, I think of it more as the ability to control a materials luminosity. Just some caution here, use extreme caution when setting emissive levels, and only do this on materials where needed. When using this to deal with the overall interior ambient there are really only 3 surfaces involved, ceiling, walls and floor. Another cautionary note, the larger the surface the greater the effect is for any given emissive level setting. To begin with, I usually adjust the largest surface which is the walls, open up the wall Define Material DBX, make sure the  Material Class is set to General, emissive is not available for any other class of material. Use a very low emissive setting, I usually start with 0.01, make sure to Tab before pressing  OK otherwise the setting may not stick. If too bright or the wall surface looks too fake or cartoonish then reduce the emissive level, if everything is still too dark then increase it, just use small value increments. In many situations the walls are the only item that needs this adjustment, If you need a bit more but the walls are at their limit then switch to the ceiling and make some adjustment to it. Keep in mind that this has it's limitations, unlikely to have the perfect sunlit interior but it should be good enough to start working on your other lights.

 

There are of course other techniques using area lights but the above approach is straight forward and fast.

 

Hope this proves to be of help.

 

Interior with Sun only adjusted so background looks correct through windows. Sun Intensity 10.0 Lux.

 

Same Interior as above but wall material has emissive set at 0.05

 

How it would look if I just kept cranking up the sun to brighten the interior. Background overexposed, significant color cast.

[Designer1]

Wow thank you so much for all the recommendations and advice!  Its nice to know there are several options to remedy the shadow problems.  I will try each of recommendations made on here and see which one works best for this plan.

 

Thank you both for the replies and I appreciate all the time and effort.

[Designer1]

I have been working on the PBR and there are lots of benefits to them but can see what everyone is talking about with some of the limitations as well.   I like the shadows in raytrace and don't like the blocky look of the shadows in PBR.  Does anyone know if theres a way to somehow copy and paste into our library the 3d shadows used for non 3d trees in raytrace so we can manually place them in the PBR?

 

I know Im probably grabbing at straws for this idea but though id throw it out there.  I figure each non 3d tree has the have some kind of shadow to its file... too bad we couldn't at least place a 3d tree in PBR, turn off its shadows and then place the non 3d tree shadow behind it so it looks more real. 

 

I better go walk my Pug Im too wrapped up in everything ideas in Chief!

[Donco15]

This has been a very helpful topic.. Thanks for the specific details @TheKitchenAbode

[TheKitchenAbode]

11 hours ago, Designer1 said:

I have been working on the PBR and there are lots of benefits to them but can see what everyone is talking about with some of the limitations as well.   I like the shadows in raytrace and don't like the blocky look of the shadows in PBR.  Does anyone know if theres a way to somehow copy and paste into our library the 3d shadows used for non 3d trees in raytrace so we can manually place them in the PBR?

 

I know Im probably grabbing at straws for this idea but though id throw it out there.  I figure each non 3d tree has the have some kind of shadow to its file... too bad we couldn't at least place a 3d tree in PBR, turn off its shadows and then place the non 3d tree shadow behind it so it looks more real. 

 

I better go walk my Pug Im too wrapped up in everything ideas in Chief!

 

You can soften the shadows by using one or more lights placed outside with their shadows turned off. Their light will dilute the hash shadows produced by the sun, you use them as a means to control the overall ambient light. Properly placed and adjusted they can be used to not only dilute the overall shadows harshness but also to soften the shadow edges, providing a more gradual transition from shadow to non shadowed regions.

 

[Designer1]

Graham, thank you for your suggestion!   Can you tell us more about how you position your type of lights and the lumens you recommend?  I used a light out in the landscape to mimic sundown light on the side of the house tinted orange and set it about 200" above the ground @1200 lumens.   I have not used it for reducing tree shadow harshness.

 

Using these lights to reduce tree shadows how close to the trees do you place them and at what lumens?  How do you prevent these lights from lighting the other areas of the scene?

 

 This whole PBR experience is so different then raytrace that its really taking some getting use to the new way of thinking of the rendering process.   I sure appreciate you and others help and guidance with the PBR's Im finding it to be very informative.

 

Thanks!

[Designer1]

Graham, I tried adding four lights to the plan and even ramped up the lumens to a ridiculous amount to see if it would make a difference but it didn't.  For some reason when I toggle off the sun the lights show up but when I switch the sun back on they disappear and make no difference to the trees shadows.  I have to be missing a lighting option to get this to work.  Heres a couple pictures of what Im talking about.

 

Thanks!

[TheKitchenAbode]

Chad, in the rendering it does look as if the shadows have been reduced. What is the lux intensity of the sun? and what is the lumen intensity of the lights? As a guide 1 Lux = 100 lumen, so if your sun is set really high you will need to set those lights high. Usually when I do this I also adjust the sun, reduce it down as the added lights will be contributing to the overall brightness of the scene. Also, what are the PBR exposure and brightness settings? if exposure is set low, say for example @ o.18 CA from what I can tell does more than reduce the exposure as you would expect in a real camera, it seems to do some type of adjustment based on a maximum scene exposure level. If you add a light then it acts as if it reduces the other lights instead of just adding that lights light contribution. Can make it a bit difficult in my opinion. This is why I normal recommend that the PBR exposure be set at max, it seems to disengage this auto exposure adjustment, now when a light is added or adjusted you see it's effect as one would normally expect. Just keep in mind that if you set the PBR exposure to max then you will using in most cases very low Lux and Lumen intensities or your scene will be way too bright.

[Designer1]

Graham,

 

Thanks for all of that information.  No I hadn't looked into all those details in relation to the exposure auto adjustment you mentioned.  This does seem to be unusual but I will test these settings out, Im sure that's what the problem is.  I took everyones above recommendations for the sun and exposure when it came to interior renderings and those appeared to turn out good its the exterior ones that are iffy.  So yes, the Sun I just left on default which I think is something crazy like 100,000 lumens and the exposure is .18. 

 

So do you also set PBR exposure to max for interior renderings as well to prevent the auto adjusting or just exteriors?

 

I will test out these different adjustments and see what results I can get.  I really appreciate you giving us all a heads up on all these auto adjustments that the PBR settings do that we all might not have otherwise known about.  Thanks Graham!

[Chiefer]

On 2/20/2020 at 5:28 PM, Designer1 said:

Can anyone give me any lighting advice on how to lighten up the pitch black shadows under the island?  I was also looking at how the recessed lights don't lighten up the ceiling as well as they do in a raytrace either... so Im trying to experiment with different lighting to try and get this to look as realistic as possible.

 

This is my first PBR interior rendering.  I can see the benefits and the challenges that everyone was talking about earlier and it does take some getting use to. 

Tick Improve lighting quality

[Designer1]

Thanks Jintu!

 

I also noticed that even though I have the smooth lines when idle on some of the lines seem jagged and not as smooth as raytracing.  For instance around my windows and such... is this just my computer or do you experience this as well?  I remember there use to be final view button that would straighten that out but im not sure that works in PBR.  I also noticed that some of my metal can appear black or blue tinted for some reason.  Even if I rainbow tool click on it and its the same metal as other areas in the picture that appear accurate to the metal type.

 

Thanks for the setting recommendations... clearly the lighting, especially the can lights look amazingly better!

[TheKitchenAbode]

11 hours ago, Designer1 said:

Graham,

 

Thanks for all of that information.  No I hadn't looked into all those details in relation to the exposure auto adjustment you mentioned.  This does seem to be unusual but I will test these settings out, Im sure that's what the problem is.  I took everyones above recommendations for the sun and exposure when it came to interior renderings and those appeared to turn out good its the exterior ones that are iffy.  So yes, the Sun I just left on default which I think is something crazy like 100,000 lumens and the exposure is .18. 

 

So do you also set PBR exposure to max for interior renderings as well to prevent the auto adjusting or just exteriors?

 

I will test out these different adjustments and see what results I can get.  I really appreciate you giving us all a heads up on all these auto adjustments that the PBR settings do that we all might not have otherwise known about.  Thanks Graham!

 

Just my method, but I do the same thing for interiors, start with the PBR camera Exposure set at max and the Brightness set at max. Typically with these settings the sun intensity will only need to be between 5 - 100 lux. I only adjust the Camera Exposure and Brightness once I have all my lights reasonably balance. Consider those controls to be more of a post rendering adjustment, similar to when you take a pic with a real camera and then use a photo app to make a few corrections.

 

Concerning those jaggy/torn lines, they are a bit of a problem and occur along vertical and horizontal items when the camera is on an angle. Sometimes just a slight change in camera angle can reduce or eliminate them. They can also be eliminated by saving your pic using a much higher resolution than the screens window, you can define this when exporting the image. Just a note, I have found that when saving a render at higher than the window resolution that it does not always look the same, often reflections and some other minor lighting effects come out different, you may or may not like the look.