ZBrushCentral

Decimation Master and ZB-R3

ZBrush Usage Questions
#1

Hey to all,

I’m in a little bit of a pickle here and cannot understand as to why.

I have a model with several sub-tools, totaling to around 30M polies. I used DM on each sub-tool and optimized by 35% each model. The grand total was 10M (can push this further - but here is the problem).

For some reason, after DM, my viewport started lagging like no tomorrow. I mean really badly. Imagine having 3DS Max, Maya or XSI, and having a model smoothed several time until the viewport takes several deca-seconds to respond, that’s how bad it had become.

Its not an issue if I have only 1 model showing (it still lags, but not as badly) however, I find it outstanding that a 10M model is ‘heavier’ then a full fledged 30M model.

Only conclusion I could come up with is that it loses its ‘lower divisions’, hence cannot switch to them when the viewport is being…spun shall we say? Hence only the highest SD is displayed all time.

Naturally I could be wrong, however, I would like to know if that is the reason or is there another one?

#2

Displaying a model of 30 millions of polygons with several subdvision levels and a mesh with 10 millions of polygons without subdivision levels isn’t the same.

When you are doing a 3D navigation with a model, if it have subdivision levels, ZBrush is displaying at 1, 2 or less subdivision levels and when releasing your mouse/pen, it display it at its full resolution. To explain that with an example.

Imagine the demo head with 7 level of subdivision (14 millions of poly), then, rotate it. If you take a close look, you will see that the topology is displayed at a lower level of subdivision, the 4th level in this model which is only 228 000 polygons. Release your pen, it will switch back to the level 7. ZBrush is doing the job for you, and except a short lag when picking the model and release it, you won’t notice it.

For a Decimated model, you are losing your levels of subdivision, then, ZBrush must display all the polygons and can’t use this “trick” of displaying it at a lowest level of subdivision since you don’t have them anymore.
Just to do a test, remove the lowest level of subdivision of your original model before decimating it and try again :slight_smile:

Combine that with several subtools at the same time, and then, yes, your viewport can lag. It’s not a bug at all, it’s just the way it works :slight_smile:

I hope it helps :slight_smile:

#3

Ah, well, that confirms it then.

Thank you very much my kind Sir.

#4

You’re welcome :slight_smile: