'Maya'

 
'Modelling and Rigging a nut and bolt'
by Martin Andersson


This tutorial will go through the steps to create a photo realistic model of a nut. It requires that you have some basic modelling skills.

There are a lot of different nuts out there and you can use the same method creating them all. I'm going to model the one in the image


You can use this reference image that I used to follow this tutorial or you can use your own reference and just stick with my method if you like


1 - The image's measurements are 68 by 96 pixels.In Maya create a pPlane ( polygon plane ) and rename it "pReferencePlane".

Rotate it -90 degrees in Y and 90 in Z. Move it -6 in X.

Under INPUTS type in Width 6.8, Height 9.6 and set both subdivisions to 1.

Create a lambert and call it "lambertRefrenene".

Double click it and click the checkerboard to the right for the color attribute. Now choose file and browse to the gif above. ( Since it's a gif Maya will make it transparent for us too )

Now apply this material to the plane by middleMouse-draging it onto the mesh or by selecting the mesh,rightClick the material and choose "Assign Material to selection".

Click for larger image

Now I want to set up some 3d reference. "huh, 3d reference?" you might think, but I like to have a visual of how the mesh will look so I use NURBS to "cage" the model. In this particular example I also need a place-holder to help me place the pivot of my NURBS objects. Sounds confusing? Well, it's not. I'll do it step by step below. Important: Make sure you don't move anything away from the worldspace origin!

2 - Create a cylinder and set subdivision axis to 6.
Scale this up to match the size of your reference.
( It's still important that you remain in the origin ).

Now use the sideView to draw the countor of the
flat side of the nut facing the camera. I use EP-
curves
to draw these. The top- and bottom curve
are drawn with the curve degree setting on 1
linear
while the other ones were drawn using
3Cubic. When you have drawn this, group the
curves and call the group "nurbsGrp". It's
important that you draw the top- and bottom
curve to match the geometry of the cylinder and
not the reference image.

Move the group so it allignes with the side of the
polygonCylinder.

Now we can snap the pivot of the group to the
origin ( 0 0 0 ) To go to pivot mode press "insert"
on your keyboard ( above Del ) To snap
something to the grid you hold "x" while dragging
the item you want to snap with the middle mouse
button. When you're done, hit "insert" to go back
to default mode.

Click for larger image

Click for larger image

3 - Hint: You don't have to press insert to go into pivot-mode. Hold "d", then hold "x" and do the same operation as above. When you release "d" you'll go back to default mode again.

Now I want to duplicate the NURBSGroup 5 times to get the rest of the "walls" for my nut. I select the group
and go to "Edit Duplicate ". To the right of
"Rotate" you can see three floatFields. These represent x, y and z. I want to rotate the new duplicate 60 degrees in my z- axis. I type in 60 there and I also type in 5 in "Number of copies". 360/6 = 60. There are six sides on this nut so I need five more and they should rotate 60 degrees because there are 360 degrees in a circle.

Remember to go into the duplicate Options and reset
the tool for future duplicating :)

I have used NURBS Circles to draw the contour of the rest of the nut. I placed the circles where I found it
reasonable to have them since I do not have a top
reference for this one.

 

Click for larger image

If you want to have red circles like me, you simply select one and go into the attributeEditor. Under "Object - Display Drawing Overriders" you can check "Enable Overriders" and choose a color on the colorSlider.

Note that "caging" a model like this is not necessary, but when I don't have any deadlines I like to do it to get a total impression of how the model will look. It can also help you plan where to put your edges and therefore give you a good polyCount. These NURBS Curves can be useful for snapping later because you can snap vertices to curves. But once again, if you have a tight deadline, don't bother doing it.

Enough NURBS- talk. Let's jump over to the polyModeling. Talking about NURBS tend to get people puking.


4 - This is the time when you choose between using a pPlane or the "create polygon" tool. Last time I did
this model I used "create polygon", but this time I
used a pPlane and to be honest, using the plane is
less timeconsuming. By default Maya creates a plane with a subdivision width and -height of 10. We only need a width of 4 and a height of 1. Rotate the
plane -90 in Z.

When I created this plane I noticed that my NURBS-
cage and my referencePlane was a bit off the origin.
I moved them so the new plane hit the curves in the
corners. It's more important to have the new plane
in the origin than the cage and the reference

When adjusting the plane, try and get the same
height for all the faces.

We want the mesh to be perfect before we move on. When you feel that you have done a good job here scale it down a tiny bit and select all the outer edges. Extrude them so that the new edges fit the cage again ( Edit Polygons Extrude Edge ) Make sure you're in modeling mode (F3) to get to the "Edit Polygons" drop- down menu


Click for larger image



Beginners_Guide_to_ZBrush



As you can see on the image above, I duplicated the new plane ( from now on renamed pNutWall ) two times.
One to be rotated down and one to be rotated up. My plan is to only create a cake slice and duplicate it
5 times to merge the whole mesh ( just like I did with the first NURBSGrp ) The reason I duplicated these two
is so I get to see how the top and bottom on the pNutWall have to look like to smooth correctly 'cause trust
me, the way it looks right now will not result in a pretty smoothing.

I will combine ( Polygons Combine ) these three three walls and merge (Edit Polygons Merge Vertices )
the vertices that overlaps each other so I have one mesh to work on. I would like to have direct feedback on the smoothing so I create a smooth proxy. "Polygons Smooth Proxy ".

Reset the settings in the optionBox ( Edit Reset Settings ) and under the frameLayout "Display Settings"
choose Smooth Proxy Shader - "Keep". Then hit "Smooth".


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