ZBrushCentral

Pen lag/ Jittery stroke. lots of testing done- Please read!

i’ve done a buttload more testing with the whole pen lag/jittery stroke thing.
i’m all but convinced the problem doesn’t exist with the tablet itself or the driver, rather in the program itself (i could still be wrong, though as i really don’t know what 'm doing). here’s some recent problematic findings:

aside from what i’d mentioned previously, i tried setting up a controlled situation with versions 4, 4r2 and 4r4 P2.
i generated a polymesh sphere from the popup and got it in the vicinity of 2 mil polys. hit F to frame it.
in zbrush 4, there was no instance of pen lag while tracking along the surface of the mesh. when applying a somewhat rapid spiral stroke with the clay brush, i also noticed no lag or jittered/irregular stroke. so i tried a succession of rapid side by side strokes that were about a third of the radius of the sphere (about 4-5 inches long on my screen). no problem whatsoever.
for all the tests, the draw size was at 64 and the z intensity and focal shift left untouched.

fired up 4r2 and tried the same situation. while i noticed no issue with the tracking on the 2 mil. polysphere, it did start to lag just a bit, when doing the spiral stroke, if i did it really fast. with the rapid side by side strokes- no jitter or anything.
so i decided to dynamesh the sphere at 1024 (about 2.6 mil polys) and repeat the test strokes of both variety.
no change. seemingly identical results.

on to 4r4 P2, where the real fun began…
same situation. polysphere, divided to about 2 mil. tracking along the surface was a bit off. the faster you drag the pen, the more the red cursor would lag. during the 2 stroke tests, the lag and stutter was alot more pronounced than in 4r2.
dynameshed at 1024… performed overall a little bit worse.
so then i tried Qremeshing and got the resolution to about 1.6 mil. polys.
a bit less, but i figured fine for the test.
this is where things got awful. the tracking lagged nearly twice as much. stuttering and lagging while doing the stroke tests was greatly increased. so then i decided to turn on X symmetry…
when doing the spiral test, it lagged so much, that it didn’t even draw a spiral. i got a very broken, jittered, half drawn triangle with erratic size throughout the stroke.
it wouldn’t reproduce the short rapid strokes, either. half of them just didn’t draw and the ones that did, were all jittered and inconsistent.
so i tried hiding 75% of the mesh and repeated the tests. the overall effect had lessened a little bit, but still god awful.
i tried qremeshing several times to arrive at different resolutions, with different methods (used the slider, half, double, etc.)
basically after using Qremesher, even though the topology was very even- it left the mesh all but unsculptable (unless you draw strokes REALLY slow. too slow to be practical)…
which is a real shame, considering all the possibilities with Qremesher.

i also noted that 4r4 P2 starts up noticeably slower than 4r2 and 4. it also loads files slower, as well.
in fact, 4 loaded the quickest, 4r2 a bit slower and 4r4 P2 being the slowest.

so i don’t have any idea what this all means… i don’t think it’s a pen driver thing. i’ve tried multiple drivers, arriving at the same results. using the “atmonitor” utility, to show CPU usage- versions 4 ran at about 70-80%. 4r42 fluctuated from 70-95%. 4r4 runs at 96-99% constantly.

really hoping something gets figured out here. i use zbrush for work and presently it’s really gumming things up for me.
thanks for taking the time to read!

Try running the Multithread test to see if there’s some differences there. This is found under the Preferences->Performance menu.

You can try a couple of different settings in here but don’t forget to change it back if you need to.

Try changing the Multithreaded Steps. On one of our computers we had to change this to one less than the auto default number. In my case it was a 5 and setting it to 4 made a huge difference with pen lag. This doesn’t seem to be the case with R4P2 for me but you could try it on your machine and see if it makes any difference.

no dice, i’m afraid. i had run the optimizer with no real change (at least noticeable).
i tried each and every step in the multithread steps slider. didn’t see any changes for the better, it only seemed to get worse for me, so i left it at 6, where the optimizer put it.

thanks for helping a brother out, though!

Thanks, zber.
I tried this and noted no real change… I tried multiple settings to no avail, either.
i’m out of town at the moment, but when I return- I’ll give it another go just to be sure!