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"Splitting renders"

Author: Herodino

Tools Needed

  • Bryce
  • Any photo editing tool

Introduction

This tutorial explain how exactly split a render. Rendering high resolution image/video always take a lot of time. If you don't have a powerful machine the system will be completely busy during all this operation and you may absolutely avoid power shut-down; splitting the render allow you a best management of your machine work-time. From the opposite side you may have a powerful computer and noticed that Bryce use only 50% of your system resources (e.g. multi-core processor or gigs of RAM) and you cannot increase the render speed. You can split your render and open two or more session of Bryce in the same time, doubling (or more) you're rendering speed. NOTE: Obviously you must finish preparing your scene before split your render!

Step 1 - how many parts?

First you must decide how your render will go to be split.

If your problem is a slow machine you may decide the maximum amount of time you want to use your computer in one time. So try to estimate what's the max dimension of the image you can render in this time.

Example1:

You've prepared your scene without materials and you know that rendering with materials take quadruple time: you may decide to split your render in 4 parts.

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Example2:

You've prepared your scene in 800×600 resolution and want to final render your image in 2048×1536: you may decide to split your render in 9 parts.

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If you want to completely use your powerful system resources you must take the same choice.

You must control how the rendering operation busy your system (in windows simply start the task manager) to decide how many rendering sessions you can start at the same time.

Example3:

Your system: dual core processor, 3 GB RAM.

You notice that Bryce use only 50% of CPU and less than 1, 5 GB of RAM, so you can start two rendering session without loss of speed. You may decide to split your render in two parts.

NOTE: Both CPU and RAM must be unemployed or you may have a lower rendering speed. Doubling 50% CPU usage and 70% RAM usage make your system use 100% CPU (not a problem) and 140% of RAM (40-50% hard disk swap memory).

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NOTE: you can split renders in every way you want, only assure the parts are equals. (e.g. 4 parts can be 2 rows and 2 columns, 4 rows or 4 columns)

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Step 2 - document setup

Now you know how many parts your image will be split, so you must calculate the part dimensions and set the document.

You may choose chessboard o linear distribution.

Chessboard distribution means that you divide your image in a matrix of regular columns and rows proportional to the original image, this way allows you to use original proportion, but oblige you to scale the view.

The linear distribution force you to change the document proportion but you may not change the view scale.

Examples split for chessboard parts distribution (a) and linear parts distribution (b).

Example 4a:

Final image resolution 4000×3000, 4 parts 2 rows 2 columns.

Single part height: 3000/2=1500

Single part width: 4000/2=2000.

Example 4b:

Final image resolution 4000×3000, 4 parts 4 columns.

Single part height: 3000

Single part width: 4000/4=1000

Open file menu, than document setup. Assure that 'constrain proportion' checkbox is un-selected, and set the part resolution in 'document resolution'. Click OK.

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Step 3 - set the camera scale (only for chessboard distribution)

If you want to split your image like a chessboard you must zoom the camera to enlarge the view of the single parts.

The zoom is equal to numbers of rows/columns: 2 rows/columns zoom 200%, 3 rows/columns zoom 300%, etc'

Click on the second from top arrow on the side of the view controls, than select 'edit current camera'. Set desired zoom in the 'scale' box.

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Note that you must set the camera scale only for the first part because the settings still remain if you don't reset the view, so don't reset the view for every part, your work will be faster.

Step 4 - set camera pan

Now you must move the camera in the right position. The pan value in the 'edit current camera' window show the distance (in pixel) of the view's center from the real camera position (standard set is 0 both for vertical and horizontal pan and means that you are viewing from the center of the camera).

You must calculate the distance from the camera center and every single part (center) you must render.

Sketch a scheme of your image with dimension and calculate the distance (in pixel) from the center of the final complete image and the center of every single part (it will be an elementary subtraction, don't worry!).

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Note the sign of the pan.

For the horizontal pan left is positive and right negative.

For the vertical pan up is positive and down negative.

The sign change at the center of the final view (0, 0).

If the sign is '+' you may not write it, in the tutorial is only to ease explication.

Example 5a

Easy to calculate for every part: final image resolution/2 – part resolution/2

Part1: pan h +1000 pan v +750

Part2: pan h –1000 pan v +750

Part3: pan h +1000 pan v –750

Part4: pan h –1000 pan v –750

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Example 5b

Pan v is every time 0

Part1: pan h (final image resolution/2 – part resolution/2)= +1500

Part2: pan h (final image resolution/2 – (part resolution + part resolution/2))= +500

Part3: pan h – (final image resolution/2 – (part resolution + part resolution/2))= -500

Part4: pan h – (final image resolution/2 – part resolution/2)= -1500

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You can set pan in the 'edit current camera' window.

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Every time you set pan h and pan v for a view click OK and save the view in a memory dot.

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Step 5 - save the document

Now save the document.

You may need to save many time if you need more than 7 memory dot to save your views, don't worry that's not a problem save the file with another name than empty the memory dot and use it!

Step 6 - start rendering

If you have a powerful machine start another Bryce session and open the file another time.

Start to render every single part and save it with different name.

If you opened other sessions, start a different part rendering for every sessions and save images with different name.

For best part management of 'super-fragged' images create a naming system for easy find every part position (e.g. name rows with letters from up to down 'a, b, c, d, etc' and columns with numbers from left to right '1, 2, 3, 4, etc').

Step 7 - joining images

After all images are rendered. You must join all the images with a photo editing program (e.g. Photoshop, corel PP, Ms paint).

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Assure to use a SNAP system or something to exactly position your part quickly avoiding distance or overlaying of the parts.

SNAP is an option that automatically align object forcing contact from specific points (e.g. images margins) for different program it can be named in different way (like 'align'). The only thing you need is an help to quickly place every parts in the correct position.

Step 8 - saving final image

Now you have your final image.

Save it and make some post-production if you want.

Bye!

Let me know if you have some problem (pm in Bryce general discussion forum)

HERODINO