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# 1 28-10-2007 , 07:46 PM
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Combining Vertices/edges!

i think imma freak out...I've been working on a training material that i bought digital tutorial. Its some sort of space bike. But i model the first half of the bike...then duplicated it -1 on the x axis to combine the two to make one continuous object. But the training DVD that I have is scratched only in that 1 minute section so I can see how to do it. So i started exploring. I found the combine edges tool but i cant that to work to save my life...and when it actually does something it deforms the faces one side. I also tried merging vertice but it will only merge certain ones, so when i convert from poly to subD two points that need to be connected aren't. Its a very frustrating task that seems like its easier than i making it...but i just dont know the correct steps.

# 2 28-10-2007 , 08:05 PM
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Ok heres a basic rundown of what you need to do .

1 Make sure that the object you want to duplicate has it's center verts on the center Axis Line.

You can select one or all the edge verts and switch to the move tool ( in the options of the move tool turn off Keep Component Spacing)the slect the X- axis only on the move tool .Now hold down Ctrl X and Middle button drag over the Center axis on the grid and the verts will snap to the center.

2 Now you have to make sure your pivot is also on the Center axis of the grid.

To do this Select the geometry you want to mirror over the switch to the move tool.Hit insert (Ins) on the keyboard and the hold down ctrl + X and once again Middle button drag over the Center axis on the grid.
Finally hit insert again to complete the pivot move.

3 Duplicate your object then in the channel box (top right) type in -1 in the scale X.

4 Select both pieces of geometry and go to Mesh and then hit Combine.

5 Select the vertices in the center that need joining and under Edit Mesh pick the option box of the Merge and set the Threshold to 0.001 then hit apply.

You should now have one object completely joined.




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# 3 28-10-2007 , 08:27 PM
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there are some simple fules to follow when merging a flipped geometry.

first of all -> make the faceNormals show up. then you will understand better what I am talking about.


if you flip (scale in a minus direction like from X to -X) you can run into some problems afterwards. my workflow is this:

flip geometry. then do a freezeTransformation on the flipped geometry. as you can see, the normals flipped also now pointing to the inside of your geometry. this is bad. you can merge vertices from 2 objects which have diverging faceNormals but you create a nonmanifold geometry by doing so. to avoid that you freeze transformation and reverse normals. now all normals point into the same direction. when applying mergeVertex now the seam between both objects should dissappear.

if not all of your verts are merged they probably have different distance to the flipping axis. to bring all in one line quickly activate the move tool. in the tool options uncheck Retain Component Spacing (dont forget to check it again after). this makes sure the selected verts dont have a single pivotpoint. if you use the X-key now on your keyboard while moving, the selection gets snapped to the grid. since you turned off ret comp spacing all verts snap to the grid and not just the selection´s pivotPoint.

and don´t ever use instance duplication if you want to combine things! this would be bad also! XD

sorry for my bad english! hope you understood what I tried to explain.

good luck!


everything starts and ends in the right place at the right time.
# 4 28-10-2007 , 09:06 PM
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Falott it's freezing transformations on negative scaled geo that causes problems since it sets the opposite attribute and thats what causes the normals to flip.If you combine the Geo you don't need to freeze the transforms or reverse the normals but if you plan to just mirror over and leave it and want to freeze it just reversing the normals is not enough.Along with reversing the normals you have to select the geo and in the attribute editor under Render Stats uncheck Double sided then turn off the opposite attribute then recheck Double sided or you will run into problems with texturing and scaling ect later.




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Last edited by jsprogg; 28-10-2007 at 09:11 PM.
# 5 29-10-2007 , 01:44 PM
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yes, you have a point user added image I just wanted to explain what´s going on behind the scene. since i create animation ready models for realtime all day long, I ran in all those problems myself he mentioned before. I think if someone understands the basics and rules it is not so complicated anymore. now after you corrected me you did make this issue about flipping and normals even clearer I in my opinion.

have a good time!


everything starts and ends in the right place at the right time.
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