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zBrush scale changed between copies of the same zTool

ZBrush Usage Questions
#1

So I’ve been working on this Superman sculpt for a couple of weeks now. Started with a base mesh from maya, brought in to zb for sculpting and brought back into maya to create some new geo. At first everything was fine between the two but yesterday when I started the low poly I brought the obj’s out of zb and into the same maya file from before and the new obj’s were tiny compared to the older ones;

(big is orig, tiny is new)

This was annoying but since I was building/editing new geo in maya anyway I let it go. Then today while cleaning up the zTool (gettin rid of extra tools, etc) I brought in a base from posed version I made last week and found that the scale here was also drastically off;

The first is the current/final ztool, the middle is the posed version made from the same ztools using transpose master and then saving with a different filename. the last is how big the base came in when I appended it to the final ztool.

AT NO TIME did I manually change the scale in the posed scene, the only thing I changed was the canvas size for a couple bpr renders (without saving), but when checking the export settings for the individual subtools I found that while the final/original tool had scale at 1 and offset at 0 for every tool, the posed scene somehow ended up with:

Bringing the posed body into the maya scene, the scale matches up as it should but if anything the posed ztools should be the ones with messed up scale, not the orig. Changing the scale settings on the base back to 1 before appending it to the orig ztool brings it in at the appropriate scale, but from either of those tools into maya it’s tiny.

So what’s going on? Did Transpose Master change my scale settings? Did they just change on their own?

Attachments

Superman_Scale_Maya.jpg

Superman_Scale_ZB1.jpg
Superman_Scale_ZB1.jpg2511×858 495 KB

Superman_Scale_ZB2.jpg

#2

Okay…this is a long one.

Zbrush prefers a specific scale to work with. If you mesh is too large, or too small brushes will start to act rather funny. To help with this, Zbrush will scale your mesh to a size that it would like to use, it will keep these settings stored in tool.export as you have noted.
I am assuming that you haven’t been using goZ to and from Maya (though I have no idea why). The original mesh you had was way too big for Zbrush, 32.7x too big. This usually happens with obj files from Maya as maya thinks everything by default should be meters. In order to brin in your mesh with a scale and offset of 1,0,0,0 you probably appended your mesh to another tool, something else that was made in Zbrush. Any primitive 3D mesh (cube, sphere, etc) that Zbrush can create is built to the proper scale for Zbrush by default…which has a scale and offset of 1,0,0,0.
Zbrush will maintain the scale and offset of whatever the “main” tool is in the list if you’re using subtools. I am guessing that when you made your mesh go to Transpose master it reset your scale and offset to something it would prefer and kicked that out to all of your meshes when it finished.
Side note, if you put in the same numbers that you have for your scale and offset into your “tiny” mesh then it will come in to Maya the correct size and position as well.

Hope this helps to some degree.

#3

That does help explain things, thanks beta_channel:)

as for not using goZ, I use it for multiple stuff but I find just doing an obj is faster for individual subtools. On my comp (at least) goZ still cycles through the whole list even when just doing the selected tool.