ZBrushCentral

dynamesh "add" and "sub" do the same thing

ZBrush Usage Questions
#1

Hello! I am hoping someone can help me understand what I might be doing wrong or if something isn’t working as it should be. When I insert a mesh with any insert mesh brush such as the insert sphere brush, then clear the mask, and then on the dynamesh panel, hit “add” or “sub” for a boolean union or difference, it does exactly the same thing with “add” as it does with “sub”. Both buttons yield a union of the two meshes, doing exactly the same thing. If when inserting the sphere, I hold the ‘alt’ key, I get the negative mesh as expected, and then when I hit “add” or “sub”, regardless of which one I hit, the inserted negative mesh removes from the main mesh. Shouldn’t those two buttons, “add” and “sub”, do the opposite of each other? With a positive mesh insertion, I would expect to get a union with “add” and a difference with “sub”. I’d expect the opposite with a negative mesh insertion.

I tried to reboot and init ZBrush just in case, but this made no difference.

Is something broken, or am I doing something wrong?

I am using 4R6 P2 on Windows 7 Pro 64 bit. CPU is Intel Core i5 2500 3.3GHz. I have 16GB RAM. See attached for screenshot.

Attachments

zbrush screenshot boolean problem.jpg

#2

http://docs.pixologic.com/user-guide/3d-modeling/modeling-basics/creating-meshes/remeshing/remesh-subtools/
http://www.zbrushcentral.com/showthread.php?182889-I-m-having-trouble-with-a-boolean-remesh-operation%85-please-help!

#3

Thanks for the response!

I see that this can be accomplished in a different manner, using remesh, but still, it seems that the buttons on the dynamesh panel don’t work properly. Why would “add” and “sub” do exactly the same thing? That doesn’t make any sense. It seems that those two buttons are actually completely pointless as they operate now, as I could just do the ‘ctrl’+click+drag thing to dynamesh and weld the insertion to the main mesh. You’d expect at least “sub” to offer different behavior. The “and” button does indeed do what I would expect. It yields a proper intersection. But strangely, it only does something different from “add” and “sub” if the insertion is negative. With a positive insertion, it does the same thing as “add” and “sub”. Something doesn’t seem right here.

It appears to me that somewhere in the code, the “sub” button was mistakenly set to do the same thing as the “add” button, maybe just needing a sign change or something. Or does it only yield different behavior in certain contexts? Why do these two buttons exist when they don’t do anything different? And if they don’t work, if the proper way to do this is to use “remesh all” in the subtool panel, why are those dynamesh buttons even there?

Also, if you mouse over the “sub” button and hit ‘ctrl’, the description says that any inserted mesh will act like a negative mesh. It doesn’t work as described. Even though the “and” button strangely only yields different behavior with negative meshes, at least this is reflected in the description for the button.

#4

They don’t do the same thing for me. Make sure that the object you’re using to subtract has less polygons than the other one.

#5

I made sure of that, actually trying in different cases with the inserted mesh having less and more polygons. In either case, I get the same behavior for “add” and “sub”.

#6

OK, here’s what works for me.

I have an tool in one layer. I dynamesh it.

I have another subtool, below the first. I position it the way I want.

If I want it add, I leave things the way they are…If I want it to subtract I click on the subtract button.

Then I go to first subtool, click on merge down, and re-dynamesh.

Presto, it works, it either adds, or subtracts as specified.

#7

same problem here.SO i use “ALT” key all the way.

#8

Gordon,

Thanks for that. But that just sidesteps the issue, doesn’t it? Even when doing that, the “add” and “sub” buttons do the same thing. If the “sub” button would do what it is described to do, it would offer a much quicker way to do it. Using your method, you use the insert sphere brush, clear the mask, go over to the subtool panel, split to parts, click the little boolean button on the part to set it to subtract, merge back together, and finally, trigger dynamesh. Whew! That’s really inefficient!

Of course, we can just use the ‘alt’ key when using the insert brushes. But still, why the “sub” button? It seems broken. It would be useful if it would work, as if you forget to hit ‘alt’ and then spend time to reshape and position the insertion, you could just hit “sub” and you wouldn’t have to do it all over again. Also, after you hold ‘alt’ and insert a negative mesh, sometimes it is hard to see what you are doing with it since you can’t see the front faces. If the “sub” button worked, you could just insert a positive mesh, position as you like, and then hit “sub”. See what I mean? And it would be so much quicker than all that stuff on the subtool subpalette with splitting and merging and whatnot.

#9

Yes "add"and “Sub” works the same for me too. “And” button works perfectly.

I could not find the way to add and sub in on a single dynamesh operation. But for all other cases it´s quite simple rule:

The last IMM inserted will determine if all others will be additive or subtractive when dynameshing.

So if you drag all positive and the last one you drag with Alt and move away from object, yes it will subtract all your positive meshes! Nice trick

If want the AND operation you need to drag you mesh with ALT pressed, then clear mask and then press “And” button.

Hope this helps

#10

OH, I didn’t realise you wre talking abuot eh buttons in the Dynamesh panel. I thought you mean the icons in the subtool palette.

I thought those buttons haven’t done anything since the very first itteration

#11

So, is that the answer then, that the “sub” button on the dynamesh panel really is broken? It sure seems to be. I hope it gets fixed by next release, or removed if nobody is going to bother fixing it. It seems silly to have buttons lying around in the interface that don’t do what they are supposed to, just lying in wait for the unsuspecting user, ready to suck them into hours of hair-pulling, nail-biting frustration trying to understand how to use the feature! :wink:

Also, I learned that there is another way to subtract an inserted mesh if you didn’t hold ‘alt’ to make a negative mesh. Just hit the button on the polygroups subpalette labelled “group as dynamesh sub” and then ‘ctrl’+click+drag in empty document area or hit the “add” or “sub” button on the dynamesh subpalette. Here again, annoyingly, “add” and “sub” do the same thing.

Does Pixologic read these forums? Is there some proper way to report a bug or broken feature other than talking about it here? Should I submit a ticket with Pixologic tech support or something?

#12

Yes they do read.
I don´t think reporting a support ticket will solve anything with your workflow in Zbrush. Much better to post here so you will have some answers from different people that could help you to understand different ways to solve a problem in ZBrush. Also it could help some people in your same situation.

#13

I don´t think reporting a support ticket will solve anything with your workflow in Zbrush.

Mostly, at this point, I’d just like to draw the attention of the Pixologic developers so that they can fix it if they aren’t already aware of the problem, since the “sub” button in the Dynamesh subpalette clearly seems to be broken.

#14

I´m pretty sure they already know about this buttons behaviour. But of course it´s a customer service so use it if you need. I used it and it´s an absolutely great service.:+1:

I mean posting here it´s always worth because you will probably have fast and enough acurate solutions for your future problems with ZBrush.

Also consider Moderators and Developers replies questions in this forum threads quite often and they did this thread for this purpose, so other users could solve their issues too. :wink: