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slow speed of simulation on Palm Island 
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Post slow speed of simulation on Palm Island
In preparing to teach RobotC, I've been running the challenges on Palm Island, but on my lenovo X61, an otherwise speedy machine (3 GB ram with an Intel Core2 Duo running at 1.60 GHz), the speed seems very slow... For instance, to turn the robot to the right takes 15 seconds, a very long time in the life a student trying out different code. Any suggestions on how to speed things up a bit on Palm Island? - trulyBoule


Thu Oct 06, 2011 8:02 am
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Post Re: slow speed of simulation on Palm Island
You are right, that is way too long to keep a student motivated. I am using a Lenovo also and I don't have a graphics card and I am not having any problems. Can you please copy and paste your code.

Thanks


Thu Oct 06, 2011 8:50 am
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Post Re: slow speed of simulation on Palm Island
I have to admit that I don't pay much attention to computer specifications. When I want a new computer I send a note to my IT guy and tell him to purchase me a great computer (I get a new computer every two years)

Trudyboole, I sent your note to Tim Friez (our IT wizard) and here is his reply:
Quote:
Robin, Your Lenovo does have a discrete graphics card (i.e. a stand alone graphics card). Just because you have a Lenovo doesn't mean your performance is equivalent to every other Lenovo's user. It's like someone saying "I own a Ford", where you have a Mustang and they have a Pinto, and calling them equivalent in speed.

This customer's experience sounds exactly like the issues of running Robot Virtual Worlds on a computer that has an integrated (i.e. built into the processor, not a stand-alone card). Performance on these lower end machines is pretty terrible.

The Lenovo X61 is an "ultralight" computer where they sacrifice video graphics and performance in order to make the computer very lightweight. It's also a computer that was released in 2007.

This was the issue we had with the classroom computers until we bought them video cards... the problem is you can't "buy a video card" for a laptop computer.

I think this is an issue of the customer not meeting the minimum specifications for using the software and complaining that it doesn't run as expected. I would point the customer to this page: http://www.robotc.net/download/rvw/specifications.php


Thu Oct 06, 2011 10:28 am
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Post Re: slow speed of simulation on Palm Island
Thanks, Robin and Tim,
That info really helps. We loaded onto an AlienWare laptop and it flew! We're going to be working with our IT folks: they'll see if they can boost our 3D rendering with some software upgrading. It'll be trial and error for a while, but I'll get back to the forum with anything that helped boost our X61s. Again, thanks for the fast responses....
trulyBoule


Thu Oct 06, 2011 12:27 pm
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Post Re: slow speed of simulation on Palm Island
Just curious, if this is really related to graphics performance, the kids are playing 3D first person video games on their laptops and they don't have performance issues with them. In fact, the resolution and frame rate looked awesome with these video games. Is there a reason why RVW's graphics performance is so much worse?


Thu Oct 06, 2011 12:41 pm
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Post Re: slow speed of simulation on Palm Island
Think about the amount of data that the RVW physics engine is attempting to calculate.

Think about the sonar sensor alone. In order to simulate the behavior of the sonar sensor picture an array of points being sent out that consists of about 20 laser beam like vectors with its cone in the center and projecting outward at about 35 degrees. (see the image below) Each of these vectors returns many values in milliseconds. Multiply the number of vectors (30 plus) that we are using to simulate the sonar sensor times the number of data-points being captured per millisecond (some of which you can see using ROBOTC's real-time debugger) and you begin to see the amount of data the physics engine is required to calculate. This doesn't include data from the scenes or other physics related properties. (then add the touch, light, compass, and encoder)

The video games are receiving feedback from a joystick or mouse; one data point. We are asking simulated the RVW computers to process many data points and using this feedback to control robots and other objects in the simulation.

There is no comparison between the amount of data we are having the computer process and most computer games...


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Thu Oct 06, 2011 1:09 pm
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Post Re: slow speed of simulation on Palm Island
In other words, the performance issue is not really related to the graphics card. It's more about the CPU performance. I am assuming the physics engine runs on the main CPU of the system and has nothing to do with the graphics processor. I had a wrong impression from reading the posts that it had something to do with the graphics card. But then why would you say replacing the graphics card will improve the performance?


Thu Oct 06, 2011 1:27 pm
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Post Re: slow speed of simulation on Palm Island
Graphic cards allow onboard processing of data helping to facilitate computer processing. We have seen significant improvement of RVW performance on older computers when we installed graphic cards.


Thu Oct 06, 2011 1:57 pm
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Post Re: slow speed of simulation on Palm Island
Thanks for clarifying.


Thu Oct 06, 2011 2:00 pm
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Post Re: slow speed of simulation on Palm Island
On the very simple Challenge 2 of Palm Island we also see 15 second turns using our wimpy Dell laptops. Over 30 seconds to drive forward through Challenge 1. No sensors at all, just motors running.

Reducing the color to 16 bit and reducing the resolution have no effect on the driving speed. It does not seem to be a graphics issue.

Why is it so slow when there aren't any sensors?

Are you saying that you actually do your sensor/robot/world interaction calculations on the graphics card?


Sat Oct 22, 2011 1:30 pm
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Post Re: slow speed of simulation on Palm Island
We use the Nvidia PhysX engine since it is the bundled physics engine with Unity3D. PhysX will use the graphics card if it is available: http://www.geforce.com/Hardware/Technol ... technology

If you're experiencing unacceptable frame rates, please post your computer specifications; especially the model Video Card, the amount of VRAM on the card, your processor type, processor speed, and the amount of system RAM.

This will help us get a better idea of what sort of systems are having trouble running the RVWs.

Thanks!

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Wed Oct 26, 2011 10:21 am
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