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Tema: Rendering with Povray from Blender

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    Rendering with Povray from Blender

    Rendering with Povray from Blender
    José Mauricio Rodas R. "Morfeus"





    Although Povray is excellent ray-tracing software, Blender users did not have many ways of using it cleanly until the release of Blend2Pov. Although Blend2Pov was born as a script, just like the JMS Blender-to-POV exporter, the script exported the XML generated by Blender for Yafray to a POV format. Now in their latest versión (0.0.6a at the moment of writing this article), Ramon Carlos Ruiz (RC Ruiz, the script author) has successfully integrated it as the render UI within Blender (Figure 1). This provides almost seamless integration for PovRay, based on clever usage of the Yafray code. This article will teach you how to use Blend2Pov.

    Installation
    To make it work, you will need to install the Blend2Pov binary which you can find at Elysiun, and alos the newest versión of Povray. You may alos want to install Megapov, as it is compatible to Povray and has additional features like HDRI support and Film Exposure.

    Right now, there is no executable installation for Blend2pov, so you have to unzip the rar archive of blend2pov into a folder and rename the blender.exe to something like blender2pov.exe and copy it to the default Blender installation folder. You may alos want to create a shortcut to it for your desktop.

    Before going any further, execute the Blend2Pov program to make sure it loads correctly. If it gives some missing file errors, make sure that you placed the renamed Blend2Pov file in your Blender installation folder.

    After the successful installation of Blend2Pov and Povray, you'll be able to access it directly from Blender's Render button just as you do with Yafray (Figure 1).


    Figure 1. The Povray as Rendering Engine

    Features
    Now we will describe each one of the buttons for the Blender2Pov GUI in the 'Render buttons window'.


    Figure 2. The Povray GUI


    Bake Radio&Phot
    The purpose of this is to save the radiosity and photons data in "exp.rad" and "exp.ph" files that are stored in the default Yafray path. If you want to render an animation with PovRay, it is recommended that you render the FIRST frame with this button activated. Then, disable 'Bake Radio&Phot' and enable 'Load Previous Bake'. Finally, render the animation. Doing this will save you some time on radiosity calculations.

    Load Previous Bake
    This button is used after you have saved the Radiosity and or Photon data in the first frame of your animation. It sabes time during the rendering by using the saved data from the "exp.rad" and "exp.ph" files.

    Radiosity

    Radiosity is a technique used for the calculation of Global Illumination. Illumination is done by emitting light from each object in the scene. Objects absorb certain quantities of the energy and alos reflect some part, for what can be considered as light emission by reflection. It is done in such a way that all the surfaces in the scene act as ambient lights, and therefore each one affects the illumination of the other surfaces (well-known phenomenon as Diffuse Inter-reflection of the light ).

    The calculation of Radiosity is based on mathematical methods that are dependent on Raytracers. Povray uses the Greg Ward Method for radiosity calculation. This provides a form of replacing the old calculations (constant value of ambience) with a value of light based on the interaction of light in the neighboring surfaces.


    The quality of the radiosity is configured by default presets in Blen2Pov, which takes advantage of the stored values in the "rad_def.inc" files.


    Figure 3. Radiosity selector


    Figure 4. Radiosity options

    Now we will go through the available radiosity types.
    No Radiosity: When selecting this option Blend2Pov doesn't calculate radiosity.
    Radiosity Default: As the name indicates it loads the default radiosity parameters, the results may be bad depending on the scene, but it is good enough to make test renders without sacrificing render time.
    Radiosity Fast: This makes a quik calculation for radiosity, thus is of low quality but superior to the Default.
    Radiosity Normal: This uses typical values of radiosity for scenes where generally a good render is required, but not sacrificing too much on rendering time (for example, animations).
    Radiosity 2Bounce: This uses values of 'Radiosity Normal' but makes a double bounce of light, improving the scene. This is achieved by altering a special Povray parameter called 'the recursion_limit'. This parameter controls the quantity of times that the light interacts with an object. There is maximum of 20. In this case, the value of the recursion_limit is at 2. This alos increases the render time.
    Radiosity Final: As the name indicates, it is used for high quality renders and as you guessed with even higher render times.
    Radiosity OutdoorLQ: The low-quality radiosity rendering for outdoor scenes. It will be speedier. It is used to simulate radiosity in external scenes in which the light comes from a source of punctual light. The render is of low quality and is ideal for testing due to the low render times.
    Radiosity OutdoorHQ: This is the opposite of the previous setting and is used for high-quality renderings of outdoor scenes.
    Radiosity OutdoorLight: This is used to simulate radiosity in external scenes with the sun as a primary source of light. However, the quality is similar to OutdoorLQ.
    Radiosity IndoorLQ: This is used to simulate radiosity in interior scenes. It uses a 'recursion limit' value of 2.
    Radiosity IndoorHQ: This is used to simulate radiosity in interior scenes using a 'recursion_limit' value of 3. The render time is high so, this is best used for your final renders.

    Comparison of the quality and render times with different radiosity on the same scene:


    DEFAULT (2O sec)



    FAST (38 sec)



    NORMAL (1 min 50 sec)


    2BOUNCE (5 min 14 sec)


    FINAL ( 13 min 37 sec)



    OUTDOORLQ (32 sec)


    OUTDOORHQ ( 12 min 11 sec)



    OUTDOORLIGHT (24 sec)



    INDOORLQ (46 sec)


    INDOORHQ (25 min 36 sec)


    You can achieve better radiosity configurations by modifying the radiosity parameters inside Povray or, by modifying the PovGlobalRad value from within Blender. Remember, whenever you modify Radiosity parameters in Blend2POV you will have to generate new Bake Radio&Phot.


    Photons

    This button enables the generation of caustics in your scene. If not activated by default, faq caustics are generated, whose results can sometimes be good. The parameters of the photons for caustics are stored in the "exp.ph" file. The photons are used as helpers for Radiosity calculations.

    With Photons
    Radiosity 2Bounce (11 min 34 sec)


    Without Photons
    Radiosity 2Bounce (4 min 47 sec)



    Although the faq caustic results are not so great, these can be useful in scenes with large quantities of water (for example, underwater in a sea or a pool). In these type of environments, rendering the caustics with photons will take a very, very long time. So, it is suggested to use faq caustics here. This can be directly adjusted from Povray using the keyword caustics power, this command can have a value between 0.0 and 1.0. Note that caustics are not simulated when the value is set to 0.0. The value of caustics power is introduced as an Interior parameter of the materials.

    Jitter


    This is a condition for the área light that makes it generate a random sampling of the área light, thereby smoothing the layers of light & shadow samples. This, however, causes problems in animations as it generates random samples of the smoothness and seems to jump in the animations. See the example images for a better understanding of its effect.

    With Jitter
    Radiosity 2Bounce (5 min 14 sec)


    Without Jitter
    Radiosity 2Bounce (7 min 55 sec)



    Default Ambient
    This produces the same effect as that of Blender's 'Emit' function.

    Exec. PovRay
    The function of this button is very simple, to run PovRay for rendering as soon as render button is pressed. If Exec. PovRay is activated, the scene gets exported to the Povray format and the image is rendered directly within Povray.

    Auto AA
    If this button is pressed, the render is Anti-aliased in Povray. It is ideal for a test render. It is pressed by default. If you deselect this button, three new options will appear: AA Samples, AA Passes and Thr (AA Threshold). These new options will allow you to have manual control over anti-aliasing.


    Figure 5. Anti-aliasing options

    The AA Samples is used when using DOF (Depth of Field). AA Passes is the quantity of passes that are used in the render for aliasing. Thr (AA Threshold) is the separation value of the pixel region to anti-alias.

    Raydepth
    This is the number of bounces of the ray and is important for glass and mirrors. Higher numbers equal better results. This alos will effect the rendering time.

    Processors
    This option is currently not active in this versión of Blend2Pov.

    Gam
    Gamma is related to the OSA procedure, the oversampling of pixels that are mixed to generate the final render. The conventional rendering has a Gamma of 1.00.

    Exposure
    This addition simulates a decrease of reactive chemicals in film emulsion during exposure. The áreas that have received more light react less than other áreas. Useful for high contrast scenes as it brings out the dark áreas and limits bright areas.
    Important:
    To use Exposure you will need to have Megapov installed, since Povray doesn't support this function. If you use it while rendering, Megapov will be executed automatically.
    Conclusion
    I hope this basic explanation of the Blender2Pov parameters will get you started with using the awesome PovRay raytracer from within Blender. And, of course, as Blend2Pov develops, you will be able to use even more powerful features of PovRay with minimum fuss from within Blender.

    By
    José Mauricio and Rodas R. "Morfe us"

    www.blenderart.org
    Miniaturas adjuntadas Miniaturas adjuntadas Rendering with Povray from Blender-figure1.png   Rendering with Povray from Blender-figure2.png   Rendering with Povray from Blender-figure3.png   Rendering with Povray from Blender-figure4.png  

    Rendering with Povray from Blender-figure5.png   Rendering with Povray from Blender-jitter.jpg   Rendering with Povray from Blender-ph1.jpg   Rendering with Povray from Blender-ph2.jpg  

    Rendering with Povray from Blender-rad1.jpg   Rendering with Povray from Blender-rad2.jpg   Rendering with Povray from Blender-rad3.jpg   Rendering with Povray from Blender-rad4.jpg  

    Rendering with Povray from Blender-rad5.jpg   Rendering with Povray from Blender-rad6.jpg   Rendering with Povray from Blender-rad7.jpg   Rendering with Povray from Blender-rad8.jpg  

    Rendering with Povray from Blender-rad9.jpg   Rendering with Povray from Blender-rad10.jpg  
    Si vas a subir un trabajo al foro, hazlo adjuntando la imagen, archivo, vídeo o lo que sea, no publicando enlaces de otros sitios. http://www.foro3d.com/f45/forma-correcta-de-insertar-imagenes-y-archivos-en-nuestro-mensaje-98930.html

    |Agradecer cuando alguien te ayuda es de ser agradecido|

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