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Factors that affect performance in PhotoWorks

Question asked by Marlon Banta Employee on Mar 12, 2008
Latest reply on Mar 14, 2008 by Marlon Banta
I recently was asked during a customer consulting visit to review some of the factors that affect performance while working with PhotoWorks. I wanted to share what I had written with the discussion forum.

The list of factors that affect performance while working with PhotoWorks is below:

1 Output image size (as it is being created, the output image is stored in uncompressed format before it is converted to the desired output format; this can take a lot of memory)
1.1 There is currently a 11580 X 11580 pixel limit to the size of the output file. This is true no matter what kind of hardware is available.
1.1.1 If the user needs to render images larger than this they need to divide the rendering into smaller parts then merge them together in an image editor.
1.1.2 Note that this is the maximum limit for any machine. When you render to file, PhotoWorks does a quick calculation to see how much memory the desired image would require based on the desired resolution. If the required memory exceeds the available memory a message will appear, immediately after pressing the render button, stating that there are insufficient resources to calculate the rendering. Freeing up system resources by closing other applications might work to allow you to complete the rendering (if you free up enough resources for the desired file size). Rendering at a lower resolution would also work.

2 Hardware changes to improve performance.
2.1 The kind of graphix card that you have does not directly affect rendering performance. This is because PhotoWorks users software rendering. The best thing to do to improve performance, with your current system, is to get more RAM.
2.1.1 In this respect users benefit greatly from having a 64 bit machine because they can have more RAM available.
2.1.2 Using the 3GB switch as others on the forum have suggested will also provide a performance benefit by allowing the user to access up to 4GB of RAM. Though there are some trade offs with system reliability and the 3GB switch.
2.1.3 Though we do not rely on the Graphix Processing Unit (GPU) on your graphix card to process renderings having a supported graphix card with the correct driver is very important for the overall stability of SolidWorks. Go to to make sure you have a supported latest graphix card and the latest driver.
2.2 In selecting other hardware PhotoWorks is an application that takes full advantage of multiple processors on your machine. Users with dual core machines see their rendering times cut almost in half when compared to users with single core machines.
2.3 The last thing you could then do is to get faster processors in your machine.
2.4 Do note that for Real View in SW2008 the power of the graphix card is important (but not for the rendering).

3 Memory consumption during rendering
3.1 Windows and SolidWorks take about 1.5 GB of RAM right off the bat.
3.2 Close all other programs when you are rendering.
3.3 Close all other models in SW when you are rendering.
3.4 If you get the out of memory message for a larger rendering try the memory switch (see attached image).
3.4.1 Note that this can be a bit slower but it manages the memory a bit better while the rendering is taking place.
3.4.2 You should be sure to turn the option off when rendering smaller models that you know will render ok.
3.5 You should also try rendering lightweight.
3.5.1 Note to make any changes to the appearances that are applied you need to turn lightweight off (i.e. resolve all the models). But before you render setting the model to lightweight will save memory.
3.6 Reduce the level of detail in the model. If there are perforated sheetmetal parts or tread plate or anything that is a standard repeated pattern, these should be replicated (if possible) using appearances and decals as opposed to being modeled as features. Just as a large pattern of features can take a long time to rebuild, a large pattern of features can also take a significant amount of system resources and processing time to render.
3.6.1 Consider using a decal to mimick the look of repeated patterns. This might even be useful while modeling.
3.6.2 Consider using one of our perforated appearances (mesh in plastics or perforated in rubber). If the appearance has to be metal then you can change the illumination to be like the illumination of a metal material.
3.6.3 Use appearance surface finish to visually represent surface patterns like dimples, tread plate or knurling.
3.7 Also in SW2008 try scheduling a rendering for a time when you are not in the office (press the schedule button in the render to file dialog). Not only does it render while you are away but it also closes SolidWorks and re-opens after each rendering which makes sure that you have the most system resources available for each rendering.

4 PhotoWorks settings that significantly affect performance. Note that with each of these items you make a trade off between the desired rendering quality and rendering performance.
4.1 Increasing the number of reflections and refractions beyond what is required will slow the rendering down.
4.1.1 If a refractive model is a prominent part of the rendering then you will need to turn up the reflections and refractions to make light properly travel through the model (one reflection or refraction per reflective or refractive model faces). Too many reflections or refractions and the rendering will take a long time. Too many could mean you called out more reflections or refractions than there are reflective or refractive model faces. Too many could also mean that you called out more reflections or refractions than you need to correctly view the rendering.
4.2 Turning up the indirect illumination quality will slow the rendering speed.
4.3 Using Caustics and Global illumination will slow the rendering speed.
4.4 Increasing the anti-alias settings will slow the rendering speed.
4.5 Some appearances take longer to render than others.
4.5.1 Brushed and Satin Finish metals can take a long time to render (especially if you use accurate reflections and turn up the sampling rate).
4.5.2 Transparent glass appearances that use Dielectric Advanced for their illumination render very slowly.
4.5.3 The area light material renders slowly if you turn up the sampling rate.