OctaneRender™ Standalone v1.0 beta3.03 [obsolete]

A forum where development builds are posted for testing by the community.
Forum rules
NOTE: The software in this forum is not %100 reliable, they are development builds and are meant for testing by experienced octane users. If you are a new octane user, we recommend to use the current stable release from the 'Commercial Product News & Releases' forum.
Post Reply
User avatar
matej
Licensed Customer
Posts: 2083
Joined: Fri Jun 25, 2010 7:54 pm
Location: Slovenia

GeoPappas wrote: Sorry, but I wholeheartedly disagree with this statement. The majority of computers and programming languages are capable of vast amounts of precision.
Vast amount = still limited. Octane uses single precision floating point for its calculations, so the accuracy is about 6 to 7 decimal places.

The reason that floating point operations can sometimes result in "almost exact" results is that floating point arithmetic has an inherent rounding error, that comes from it's implementation. So the original problem is not a bug, just how real numbers representation in computers work. Here's a long & techy article about floating points (the "rounding error" paragraph at the top and following, explains this more in detail): LINK

EDIT: Of course most languages have some high-level tools to represent real numbers of arbitrary precision (like BigDecimal class in Java or decimal module in Python), but doing calculations with such datatypes is (much) slower than using the "low-level" primitive float datatype. A margin of error to 7 decimal places is enough to do nice renderings in Octane. :)
SW: Octane 3.05 | Linux Mint 18.1 64bit | Blender 2.78 HW: EVGA GTX 1070 | i5 2500K | 16GB RAM Drivers: 375.26
cgmo.net
GeoPappas
Licensed Customer
Posts: 429
Joined: Fri Mar 26, 2010 5:31 pm

matej wrote:
GeoPappas wrote: Sorry, but I wholeheartedly disagree with this statement. The majority of computers and programming languages are capable of vast amounts of precision.
Vast amount = still limited. Octane uses single precision floating point for its calculations, so the accuracy is about 6 to 7 decimal places.
Yes, but even 6 to 7 decimal places is plenty enough to store a number that is essentially an integer. The poster stated that they typed in 7 and it was changed to 6.999998. That is a bug. We are not talking about storing Pi to the 1000th place.
User avatar
matej
Licensed Customer
Posts: 2083
Joined: Fri Jun 25, 2010 7:54 pm
Location: Slovenia

To the user it looks an integer, but the program treats it as a decimal. Its about the datatype (ie. float in C++), not the actual value it holds. We don't know what conversions Octane does behind the scenes when the user inputs a number (validation, datatype casting, etc...) and every operation with floats can potentiality result in a rounding error.

I've seen this behavior (when you enter an exact number, but the program rounds it to some approximation) in other programs too, namely Blender.
SW: Octane 3.05 | Linux Mint 18.1 64bit | Blender 2.78 HW: EVGA GTX 1070 | i5 2500K | 16GB RAM Drivers: 375.26
cgmo.net
Post Reply

Return to “Development Build Releases”