Visualization Guide
Visualization Guide
Visualization Guide
Visualization Guide
Visualization Guide
Visualization Guide
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This section covers how to solve some common rendering problems.
Lighting illuminates the image. If there are no lights shining on visible surfaces, the image stays “dark.” Turn on Flashbulb to remedy this. If you are Ray Tracing, with Real World Lighting enabled, try first adjusting the Brightness and Contrast of the rendered image via the sliders in the Render tool settings.
This may be due to either or both of the following:
Screen Gamma — Make sure that your monitor display gamma value is set correctly. For photorealistic rendering, with particle tracing or radiosity, it is vital that you set the gamma correction value for your monitor correctly. With incorrect settings, you will not get the best images possible. For PC monitors, good results usually are achieved with a gamma setting somewhere between 1.8 and 2.2. The exact setting is not critical, so a good starting point is a value of 2.0.
Brightness/Contrast for Ray Traced images — When Ray Tracing, with Real World Lighting enabled, you can adjust the Brightness/Contrast of the rendered image interactively.
Shadows are cast only if shadows are on for the views, light sources, materials and:
For ray traced images, Shadows also must be turned on in the Ray Tracing dialog box.
For Phong shading, Shadows also must be turned on in the Rendering View Attributes dialog box.
Objects are rendered transparent only if the material and the view have transparency enabled.
During a design session, shadow maps for a light source are calculated when you first render a view. To save time, shadow maps can be saved instead of being recalculated each time a view is rendered. This is done by selecting Save Phong Shadow Maps, in the Rendering Settings dialog box (select Settings > Rendering > General).
When you have Save Phong Shadow Maps turned on, you must clear the shadow maps to ensure that shadows are calculated correctly, if you do either of the following:
Change the design — add, delete, modify, or move elements.
Make any changes to a light source in any way except by using the controls in the Define Light tool's dialog box.
You can clear existing shadow maps by selecting Clear Shadow Map(s) from the Mode option menu in the Define Light tool's dialog box or by keying in LIGHT CLEAR.
Noise, in the form of spots or other odd shadows, in your rendered images can occur for a number of reasons. For example, if they appear:
In the shadows of spotlights — usually due to having constructions turned on in the view, as well as the level containing the spotlights. Correct this by turning constructions off in the view being rendered.
Another reason may be that the spotlight is placed coincident with a surface. You can correct this by moving the origin of the light source slightly away from the surface.
In the shadows of area lights — usually due to having too few samples. Increasing the Samples setting for the area light should solve this problem. In general, with area light sources, the bigger the area and the closer it is to its target, the more samples that are required to produce smooth shadows. Alternatively, a small area light at a far distance would act more like a spot light (with a 90 degree cone angle) and would only require a few samples.
When shadows are off, you should not see any noise from a light source.
Other possible causes of noisy images may be:
Coincident surfaces in the model.
When particle tracing, the Smoothness setting is too low, or not enough particles have been shot. Increasing the Smoothness setting reduces noise, but can also lead to a lack of detail.
As with many other apparent “problems” with particle traced images, this can be solved by adding more particles. The more particles used, the finer the mesh used in the image, producing finer detail.
Generally, if the shadows in an image are not sharp enough, you can:
Add more particles (for Particle Tracing).
Check that the Smoothness setting is not too high (for Particle Tracing).
Where shadows are from direct lighting, turn on Ray Trace Direct Illumination (for Particle Tracing and Radiosity solutions).