Quick Note on Global Perspective

[Kaz]

I have been toying with global perspective for a while now and there was always something that bothered me. It does not always match from one object to another.

After placing an object with perspective in the location I want, I marker it. Then, I can use that marker to base other object's perspective and alignment to the first. However, if you have to translate the second object to another location, things get strange:
http://www2.zbrushcentral.com/zbc_uploads/user_image-1035146763buy.jpg

In this example, I placed the column first and set a marker. Then, using the marker and the same global perspective settings, I placed the sphere. Then, using the move tool, I moved it to the bottom of the column.

I would like to any thoughts on this and any solutions. I have one workaround and it goes like this:

http://www2.zbrushcentral.com/zbc_uploads/user_image-1035146911dcf.jpg

After placing the sphere using the marker, use Too>Modifiers>Deformation>Offset on the axis of choice. Several applications may be required to place it in the desired location.


Otherwise, I have found myself moving and rotating and resizing to get it just right.

Or maybe 1.5x....?

Any thoughts?
-kaz

[Jaycephus]

I don't understand the problem. Can you illustrate it? I was playing with global perspective (Hold 'shift' and turn on Perspective) just yesterday, using markers to build a vehicle. I placed a tire, marked it, snapshotted, and offset it. I marked it again, snapshotted, and offset to the third position, and so on. I did not notice any problems with the way it looked.

[Kaz]

First, I am using 1.5 Premier.

http://www2.zbrushcentral.com/zbc_uploads/user_image-1035217435vwg.jpg

My zscript for this does not work so here is what I did:

:b4: Draw a Cube
:b4: Use ROtate Gyro to rotate into position
:b4: Use the Scale Gyro to make it tall
:b4: Snapshot
:b4: Scale to make a short, wider cube.
:b4: Move Gyro to move it down (Grab on Purple part)

-kaz

[aurick]

I just ran a test with version 1.51 and did not encounter any difficulties at all.

I pressed Shift while turning on Draw>Perspective to activate global perspective. Then I dragged from the perspective amount slider out into the canvas to set a point in the upper left corner. All like before.

http://www2.zbrushcentral.com/zbc_uploads/user_image-1035219875pej.jpg

The lower left one was drawn like normal. So was the one closest to it. Perspective worked fine for both. I placed a marker and used it to create the big, top right one -- using all of the gyros on it. What you see has been moved, scaled and rotated with completely predictable results.

So I'd guess that the difficulties you're having are due to the fact that you're using 1.5P rather than 1.51.

[Jaycephus]

Hi Kaz,

I am using 1.51 as well. Why not re-download ZBrush and try it?

Actually, in your second post, I don't know if I am supposed to see something wrong or not. It 'looks' OK to me. Is there a problem that is supposed to show up if I go through the steps you have listed? Thanks,

[Kaz]

OK,

I am sorry for pressing this, but I have seen this in all previous version of ZBrush as well. So, if someone could try the above steps so I can be sure I am not crazy (Or that I am).

The second cube in the above example should be centered with the first, taller cube. But it is not.

Here is a ZScript, but only for example. The Global perspective feature is not being applied, only the normal perspective. So view it, the try to recreate my problem, if you would, only using Global Perspective.

Thanks....

global.txt (http://www2.zbrushcentral.com/zbc_uploads/user_file-1035240164mxn.txt)

[Jaycephus]

OK, I see the problem. My use of Global perspective in the past did not really expose this problem before.

http://www2.zbrushcentral.com/zbc_uploads/user_image-1035256704cxd.jpg

The tall block marked with the yellow 'A' is the first instance, and it is markered. All other instances were either created by creating another block on the marker, or by snapshotting a certain block and dragging from there. All movement and scaling was done with the 'constrain' parts of the adjustment ball or whatever it is called. So the result 'should' have been that all blocks are on the same planes and axes. The small blocks at the bottoms of the tall blocks should have been in perfect alignment with the tall blocks, like the bottom of an exclamtion point. The long flat plane should be in line with all four tall blocks. Instead, as each of the three other tall blocks were created and dragged away from the 'A' block, they moved off the 'line' that they should have stayed on. The long horizontal plane shows that 'line'.

This is disappointing, as I had looked forward to doing some architechtural-type of art in the near future. :confused:

I could still do something but I will have to eyeball position instead of depending on the constraints to position everything correctly.

EDIT: Yayyy! Problem Solved! :)

[Kaz]

Thanks for confirming this. :tu:

[aurick]

Hmm. I see what's happening.

I believe that this is because the gyros operate in Object space, while the global persepctive operates in World space. As a result, the new object's movement doesn't coincide with the pixols already on the screen.

For an architectural project, don't forget the power of the MultipleMarker tool! You can build your elements without persepective, allowing you to get them lined up correctly in all three dimensions and view it from all angles while you work. Then you can make the mesh and finally turn on the global perspective when you draw the assembled object. Since all pieces are one object, the global perspective will work the way you expect it to. And remember: version 1.5 now lets you combine polymeshes with the MM tool. This means that you can now build smaller pieces and then assemble them all together at the end.

[aurick]

http://www2.zbrushcentral.com/zbc_uploads/user_image-1035310019lsy.jpg

Here is a very quick example using the above method.

I created one column from 3 cubes and made a polymesh.

I then deleted the markers and made a row of four polymesh columns, using Transform>Info to position them exactly the same distance apart.

Next, I used the MultipleMarker tool again to combine the meshes into a new mesh object.

Finally, I drew the new object on the canvas with Global Perspective active. Worked like a charm!

[Mahlikus The Black]

Excellent work-around!

It brings up a very good question. Will ZB ever gain the ability to switch between object and world axis...?
That is one of the many little things that I would LOVE for ZB to be able to do!! :(

[Kaz]

Thanks Aurik.

Of course this makes perfect sense. I never did understand that there was a difference between the world space and the object space, though I have noticed its effect many times... This clears up a few things for me.

My earlier attempts at a workaround were similar to yours, though I forgot the important make polymesh part. Without that, you get some funky results...

[Jaycephus]

sdjkl;af asdfjkl; sdaf;jkl

I'm beating my head against the keyboard. I never saw anything about 1.5 allowing MM tools to be made from polymeshes!! I've been 'assuming' that that was not possible.

On the bright side, it's like suddenly getting an update that has a new feature. This 'new' feature and the fact that the problem we were having is not a bug means that we CAN do real architecture more easily! :) :tu: