This message is a warning rather than an error. It means the water calculations and rendering are taking longer than expected for the current water speed values. You may see the water animation stuttering while this message is quickly repeated.

If your sandbox is stuttering, there are a few ways to reduce the number of missed water rendering targets:

• don’t add so much water to the sandbox;
• get a better GPU;
• change the “water speed” (-ws) values at start up.

You can interactively try water speed values that work for your configuration. When you’ve found workable numbers, those values can be used on the command line during sandbox launch.

Right click in the sandbox window and choose Show Water Simulation Control. The dialog box settings can be changed while the sandbox is running. When you have values that work, use these while launching SARndbox.

-ws <water speed> <water max steps>
Sets the relative speed of the water simulation and the maximum
number of simulation steps per frame
Default: 1.0 30

I’ve never set up a second view and only use a sandbox view. My trials
were all in the primary window. Maybe try using a single view?

Our multi-monitor setup is handled by the desktop window manager and I’ve not yet tried configuring SARndbox to place multiple windows on specific screens

Can you temporarily move the Kinect to try a closer position? Or use a
second Kinect?

I suspect the posting error you are seeing means the spam filter has decided your post is too much like spam. One workaround I’ve found is to split a long post into several parts and see which one is rejected, then rephrase the problem post.

The 1m distance between the Kinect/projector and sand is a guideline. You can use a shorter distance, but it could put the projector close to the students’ head height as they use the sandbox.

Have you considered a design where the upper portion can be telescoped up and down? Our sandbox is made for portability in and out of classrooms. A link to our sandbox design can be found in my user profile.

No, sand is not required. What other medium do you have in mind?

there is a faulty detection of 2 degree slope

Have you tried re-calibrating the Kinect? Is your Kinect an older V1 model that might benefit from Per-pixel Depth Correction?

2- Create an information overlay

I have wanted to add labels to key contour lines. But, I’ve pretty much given up on this idea. In some early tests I was able to add an ellipse to the output, but I could see the GL code was not set up in a modular way. Some shader code is taken from .fs and .vs files, but is mostly composed on-the-fly in C++ strings.

The AR sandbox software is quirky. It is monolithic software that looks to have been mostly (if not exclusively) developed by one person.

For task 1, I believe I found the raw depth data, in frameBuffer.

It’s been a few years since I worked with the code, but I believe you’re correct. The Kinect::FrameBuffer is a two-dimensional array (x,y) of depth data as single float values (think of depth as a “grayscale” channel). If you want matrices, I think you could build a VRUI Math::Matrix from the FrameBuffer. But it might be just as easy to construct a two-dimensional array of correction values and elementwise add the two arrrays.

@robbo The water simulation is mostly handled in the GPU, thus the need for 3D accelerated cards like the Nvidia models. The CPU handles only a small part of the sandbox, mostly shepherding data in and out of the GPU. But, I like your idea to check the amount of “water”.

@john-m How much water is added before the framerate drops so low? Or is the framerate low even with little water?

And is the computer a laptop or desktop?

Welcome to the forum.

Are you using the -evr command line parameter when starting the sandbox? If so, is the rate a negative or positive number?

The description of -evr could be read as “positive rates evaporate water”. But, the sign of the rate should be negative to subtract water from the surface. A small, positive rate could produce the constant global rain effect you describe.

I was lucky when I tested the spacebar: the menu was so slow that I never saw it and it did not show in the screenshots. “Yay” for old computers? But I can see the menu if I hold down the spacebar for a longer time.

It looks like the F2-F12 keys do not show the menu. Try any of these in place of Space. But these keys may be assigned to something else outside of the sandbox. You can disable a key through the desktop shortcut GUI and enable it in the sandbox cfg file to use that key in the sandbox.

You’re welcome. I like to see others using the AR Sandbox, too.