render gives very good quality with people, very poor quality with primitives

soapwell

I want to put people in a store.  The renderer gives very good quality images when I put people in the simulation, even if there are a lot of them and the file is over 10MB.  This is even though I have a slow computer.  

But in a scene with even just a few primitives, the renderer is very slow and produces poor quality images.  I tried turning the Glossy settings all down to zero everywhere I could find, but I honestly wonder if the renderer is still sitting there trying to calculate reflectance variables for a whole bunch of objects in the scene even when all of them are supposed to be nonreflective.

Is there a way to force the renderer to show objects just as they are, instead of trying to calculate reflections etc?  It would help me build a scene with lots of objects in it.  

 

The file I acttached rendered very poorly despite being very simple and having no glossy objects in it to reflect other objects.  The shadowy areas are    particularly grainy.

I want to know if there is a way to make primitves such as these render as if they were "normal" objects, which to me means to render like people and clothing, which seem to do much better.

 

I've never had a problem rendering scenes with people, even with very high detail,   and even  with shiny skin.   Can anyone help?

Thanks,

Soap

Paintbox

Do you have any bought scenes? Try to render one of those and see if there is a difference.

A lot of it has to do with good lighting and good materials. Right now I see you are using the camera's light, which is just one light, which is a bit limited in its application.

Since you are new, try to take things in steps. Maybe render the example scenes in DAZ and see how they work. If you have a slow computer, use as few resources as possible to keep things fast.

 

cajhin

What exactly do you think is 'bad' in this screenshot and needs fixing?

If "slow render, grainy output" is the issue, that's probably down to not enough light. Dark areas are slow to render, and way more grainy than bright areas (same as with digital cameras).

On top of this, closed rooms are usually much slower than open areas (the light rays bounce around and around and can never 'escape into the sky').

soapwell

Thanks for the replies.

I'm new to DAZ, but I've been working with 3D models off-and-on for about ten years.  I'm not against paying for 3D models, but I will only pay for something I can't create on my own.

I could post some photos of people to illustrate how much better the rendering engine does, even on this fairly weak computer, but having tested a few things it seems that the problem isnt so much people vs primitives as it is outdoor vs indoor environments.   

On top of this, closed rooms are usually much slower than open areas (the light rays bounce around and around and can never 'escape into the sky').

Can I turn this off?  Earlier I tried amping up the luminance of the floor and ceiling, but instead of getting a clearer photo,     i    got a lighter but even grainier photo than the one I posted here.  The only way around this that I can see is to turn off all lights and have a very dark store, with just the headlamp of the camera for a light source.   

But it seems that there should be a better solution than that,  since I see others posting pictures of indoor scenes that are well-lit and dont have reflections and grainy areas all over the place, and presumably they arent all waiting two hours to render a single scene.

I dont want light rays bouncing off of objects, period.   Is there a way to make objects just render as  they are instead of having the engine waste time calculating a bunch of zeroes and infinities, as it seems to be doing?  Turning properties like glossiness, emissivity, translucency, and so on all to either zero or 100% doesnt seem to be able to stop the rendering engine from trying to calculate them anyway, and as a result producing a much worse quality image than it did before I added ceilings, walls, and floors.   

It's also possible that the engine is wasting its time calculating light beams etc that are nowhere near the camera but still part of the environment, "just in case" a tiny ray of light might enter the store from outdoors.

So I have two questions I hope you all can help me with:

 

1) Is it possible to get the engine to stop trying to    calculate   things such as light beams bouncing off of objects?  Turning all of the properties to zeroes and infinities doesnt seem to work.  I would rather just have the enging calculate shadows and nothing else.  

2) Is it possible to get the engine to limit its rendering area to just a small part of the scene, instead of calculating light sources from all over?  A real-life store is well-lit enough that the sunlight coming in through the windows has no meaningful effect on what the center of the store looks like, so I would like to shut this off as well without having to build separate scenes for each corner of each room.

 

Thank you all for your time.  

---Soap

cajhin

couple of things...

- "amping up the luminance of the floor" this means you made a glowing floor, a big light source. Quite expensive and probably not what you wanted.

- what's missing most in your scene is more light. It's a supermarket, not a dark cave. What real supermakets have is lights on the ceiling. So, add more lights.
  "Distant light" is cheap and easy, Point lights and Spotlights can give cool/realistic looks. Lots of lights are expensive, but adding 2-3 will probably speed up your renders a lot.
  One strange thing is the brightness of new lights (on the Lights panel). The default "Luminous flux = 1500" is almost nothing in iRay. Start with 500.000 and go from there.

- the headlamp is good for the viewport but make sure you don't use it in renders. It just looks bad.

- "I dont want light rays bouncing off of objects, period.". Well, no bounce at all means every surface is absolute black. You always need at least one bounce, but more looks better (light bounces off the ceiling which lights everything softly for example).

- under Render Settings > Optimization there is 'max path length'. This might be a way to limit the calculations, but I never played with it

- remove at least the wall behind the camera, some way out is better than none

- (I believe) an additional light source like a window isn't really that expensive. If you have no light outside it doesn't matter anyway

Good luck. Nice lighting is not trivial, but very satisfying when you get it right. In your case, step 1, more and then some more

Paintbox

It seems to me you lack some understanding, in the sense that you are contradictory. You wish to have realism, yet you state "Is it possible to get the engine to stop trying to calculate  things such as light beams bouncing off of objects? "
But they way to realism is the by way of bouncing lightrays, it's the core of PBR rendering. That said you can set pathlength in Iray. The number represents the number of bounces.

One tip next to the excellent ones by cajhin is to use a small meshlight, they are in general cheap to render.