OS X El Capitan and Duplicator 4S Buffering

[RyanZ]

Wow dude! Can't wait to give this a try!

Thank you so much I'll be sure to report back!

[RyanZ]

I think found the culprit, it's App Nap. That sorry excuse for a power saving feature has been around since Maverick, so I didn't check this until now, based on observations that this happens only under El Capitan (perhaps App Nap behavior changed subtly? I don't know of major changes but who knows).

You can easily try this yourself using Activity Monitor:

1. Launch Simplify3D, start a print. Wait till your printer starts printing.
2. In the Activity Monitor, within the CPU tab, right click on the column names, select App Nap. Drag it to the left so you see both Name and App Nap column.
3. Cover your S3D window completely, e.g. with a browser window or maximize the Activity Monitor or whatever. There must not be any part of S3D's UI in view, not even the title bar, nothing.
4. Wait. Your printer will stall after a minute or so. Once that happens, within a second or so, the App Nap column suddenly says App Nap is active. CMD-Tab to S3D, boom, printer resumes, App Nap says disabled. Repeat until you're satisfied.

So, what is this App Nap? It's basically conserving fuel by turning off the control-by-wire servo that powers your steering wheel if you don't steer for a few minutes. And leave it off until you yank it really really hard. App Nap basically takes apps it deems inactive (which apparently an app that isn't on display qualifies as, even if it does lots of I/O or actively uses USB connections or anything else) right out of the scheduler. No more CPU cycles, that app is frozen now.

Apple calls that a "standby" mechanism (which is horrible naming because this is at least standby mechanism #2 in OS X). Anything more complex than a word processor and this feature starts to break things, unless precautions are taken. Since it's not exactly new, most affected applications take care of this one way or another. It's also a really cheap way to make stuff appear snappier ... until you CMD-Tab to a "App Nap"ping window that suddenly needs to catch up with a lot of things. Someone at Apple also seems to have forgotten to add kernel logging for that as well ... that kernel logs next to absolutely any inane thing, but then completely freezes an app and no word reaches /var/log (or I've missed it completely).

At any rate, it's super easy to turn off, you don't even have to touch the command line (unless you want to disable it system-wide, which even I wouldn't recommend, despite all the flaming...)

How to fix this:
Go to /Applications, locate your Simplify3D app file (the one with the funky symbol, probably in a subdirectory), select it, CMD+I, tick the "Disable App Nap" checkbox. This setting needs a restart of Simplify3D to become effective. That's it, no more App Nap for Simplify3D.

I hope this works for others having the same issue too, I'm an hour into a longish print and with S3D hidden from view behind this browser window, without as much as a tiny hiccup, so I guess this did it for me. Good luck, everyone!

Dude you rock! So far its been Solid!!!!! Awesome stuff! Admin you really need to PIN THIS POST!

[1flx]

Dude you rock! So far its been Solid!!!!! Awesome stuff! Admin you really need to PIN THIS POST!

Glad to hear! I've notified support about this, they are able to replicate my findings and find them potentially very useful for lots of people, so they may decide to act on them in some way (at least put them on the website in some place or whatever).

For anyone who may stumble upon this, this is most likely relevant for anyone who uses USB printing on a recent Mac OS X with any printer, it's not at all limited to Wanhao. All devices, be it a Flashforge Creator Pro, Makerbot Replicator, Prusa, DaVinci, Rostock, LulzBot, Makergear, Witbox, DeltaWasp, Zortrax, Ultimaker, anything running Sailfish, any RepRap printer ... should pause, stall, buffer, interrupt, whatever you want to call it, once App Nap strikes. Sorry if this paragraph has turned out a bit spammy, but Google can't pick up what isn't there.

[RyanZ]

Dude you rock! So far its been Solid!!!!! Awesome stuff! Admin you really need to PIN THIS POST!

Glad to hear! I've notified support about this, they are able to replicate my findings and find them potentially very useful for lots of people, so they may decide to act on them in some way (at least put them on the website in some place or whatever).

For anyone who may stumble upon this, this is most likely relevant for anyone who uses USB printing on a recent Mac OS X with any printer, it's not at all limited to Wanhao. All devices, be it a Flashforge Creator Pro, Makerbot Replicator, Prusa, DaVinci, Rostock, LulzBot, Makergear, Witbox, DeltaWasp, Zortrax, Ultimaker, anything running Sailfish, any RepRap printer ... should pause, stall, buffer, interrupt, whatever you want to call it, once App Nap strikes. Sorry if this paragraph has turned out a bit spammy, but Google can't pick up what isn't there.

The funny thing is it was doing the same thing on my Windows 10 pc so I switched to OS X and it was working great till I noticed you had to keep it up front.

[1flx]

A little addition: Updating to Sierra somehow reset this setting for me; I had to disable App Nap for Simplify3d once again (but it still works as with El Capitan).

[1flx]

Another update: Upgrading to Simplify3D 4.0 somehow removed that little "Disable App Nap" checkbox in the finder properties view. As with any update, bundle-level settings aren't transferred to the new application file (i.e. for Mac OS X, every S3D update is a completely new application), so App Nap is active again. It's still possible to switch it off, though; it's just a bit less convenient.

Open a Terminal window (CMD+Space, write "Terminal" without the quotes, hit return). In there, paste the following command:

Code: Select all

defaults write com.Simplify3D.S3D-Software NSAppSleepDisabled -bool YES

There should be no output (i.e. just another command prompt). Restart Simplify3D if it was running and you should be fine.

[symonty]

Hi for your reference I managed to make it work using a small app from the Mac App Store.

https://itunes.apple.com/us/app/ampheta ... 4704?mt=12

I installed it and set trigger to stop Mac sleeping while Simplify was open and it worked 100% perfectly.