22 January 2009

Efficient Use of Vray Camera in Dark Room


Hello, I tried to make this tutorial as simple as possible... How do you make a picture in real life when the light is too dark? Simple: you increase the exposure time, increase the ISO, and decrease the number of frames. With the Vray camera is pretty much the same thing.

To get this result I have done the followings:

Modeling: You should pay very much attention to the modeling part of the 3D because this will affect the final result. If the modeling part is well done than the texture will display correctly and there will be no unwanted artifacts. Also keep in mind to do everything by scale, keep the proportion of objects.


2. Texturing: Texturing may take a little more time if you won’t everything to be as you wanted. So, much attention you pay to textures the better the final result will be.

Lighting: For this scene I thought... in real life I would have 1 light sources... the light from the lamp, and secondary light sources (all objects are secondary light sources in real life). So I have set the environment to a almost dark brown color, and added the two lights on the lamp. For the lights I have used an IES file that looks very cool and it is the kind of light that that lamp would project. You can have this IES file here.

Camera: As I said a little earlier we have to think with Vray cam as we think with true digital or analog SLR cameras.

Rendering: The settings are somehow basic; nothing special, just the subdivision set on higher values (1600).

Now lets talk about in little detail about the Lighting, Camera and Rendering points we mentioned above:

Lighting: This is a free point light with settings set to web and then loaded the IES file. I have decreased the power of the IES original file because the light being so close to the objects and I ended up burning the surfaces, so I have changed from 8564cd (candles) to 3564cd.

Tip: For smoother shadows you could set the Vray shadow subdiv to something more than 12 (18 give very good results), this is mostly if you have white surfaces on which the shadow can be seen much better than on darker surfaces (where the shadow is literally eaten up by the color)

Camera: You should think about the Vray camera as you would think at a camera with manual settings. For a dark environment you should set the camera with longer exposure time (that means small numbers at shutter speed) and smaller number at the diaphragm opening that means small numbers at the F-number and occasionally if the scene is really dark you should increase the ISO number (that would mean the granulation of the film or what you may call sensitivity of the film to the light - the CMOS sensor on the DSLR).

In a brighter environment it is exactly the opposite, less exposure time and higher f-numbers and also for better results you should use a ISO number of about 100 would give less noise on the picture (the ISO is used with higher rates where the scene is very dark so that the sensor would be more sensitive to the light and the indirect light from the objects)


Rendering: As I said before nothing special with the Render settings... just higher values on the subdivision and exponential color mapping with higher values (2.5) to have the darker areas lighten more.

For enclosing I have added another render with the same camera and settings, just another angle:

Authors Blog: www.kontur.ro


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