#Screw thread & Attribute
6 messages in this thread
Two questions that possibly someone can help me with:
First, I have a complicated object. It is a pump housing, kinda looks like an
odd shaped open ended tube with lots of holes in it. I want the outside to be
red paint and the inside to be shiny metallic. I spent about an hour picking
the outside faces and separating them into a new object with the red paint
attribute. It works fine but is really time consuming. Q – Can Imagine
automatically determine the outside faces and apply an attribute to them???
Second, I'm trying to make Screw Threads on a tube. I've tried most the
textures as well as the Wave command in the detail editor. Can't get it to
look quite right. Any suggestions???
Michael B.
Michael,
If your tube is odd-shaped, i.e. it curves in weird ways, there doesn't seem to
be an easy way out, as in: rotate the object so a clean cross-section appears
in one of the views, zoom in, and use the Shift key along with the lasso to
circle all outside or inside faces. Perhaps you should've split your object
while it was still a few primitives; for example, if the tube is a flat, hollow
disk, extruded along a roller-coaster path, you could've split the outside and
inside edges of the disk into separate objects before extruding. Extruding both
objects along the path would've resulted in a perfectly matched pair of
objects, each of which could've been given the proper attributes. Finally, if
your pump housing was built out of several primitives, you could've used the
previous technique as each primitive was added.
Regarding screw threads, can you give us a better idea of what your tube looks
like? Is is a simple, straight tube? If so, follow this procedure:
1) Add an axis. In the top view, add 4 lines like this:
_
| |
\ | Distance = 20 units, for example
| |
+ / _|
axis
2) In Pick Objects or Pick Groups mode, pick the axis and Extrude along Y for
10 * 20 units (200 units), with a Y rotation of 10 * 360 degrees (3600
degrees). This will spin the profile you drew and create a screw shell. The
ends, however, will look ragged.
3) Position a flat disk 20 Y units into either end, select all objects, and
Slice. Remove excess material from disk and screw. This will clean up lonely
polygons at one end of the screw, and add a cap made from the center part of
the disk. Do the same at the other end, or add a hemisphere to make the screw
head. (Slice a small slab shape out of the hemisphere to create the groove
where a screwdriver would fit)
Alternatively, when extruding you could've entered zero as X and Z final
scaling
[ MORE ]
Blaq:
Yup, the tube (pump) is really oddly shaped. I drew it in Autocad using the
AME (solids) extension to precise dimensions. AME (solids) uses 3D primitives
and boolean operations like Slice & Merge, only different <g>.
I then exported to a 3DS DXF and through POVCAD to an Imagine DXF. And, then
into Imagine. It may have been very painful to make the outside and inside
different objects during creation in AutoCad.
Anyway, I'm getting much better at manipulating points in IM3.0 8^)
And, the screw threads….
I was hoping there was some kind of texture that would make a simple tube look
really threaded. Unless I was dreaming (I lost touch with reality about the
time I got into 3D), I made great looking threads using a bump map in Renderman
two years ago. But your method of creating them is nice and easy and will work
great!!
Thanks again,
Michael B.
Michael,
if you only want to simulate screw threads, then yes, you can use a bump map.
Create an image like this:
+—————-+
|1111111000000001|
|1110000000011111|
|0000000111111110|
|0001111111100000|
+—————-+
where 0 = black and 1 = white. Wrap this around your object as Wrap Z, Flat X
(if the object is a vertical tube), with Repeat on. This will wrap a
barberpole-like pattern around your object. Warning: versions of Imagine
smaller than 3.0 do not repeat bitmaps if any Wrap option is selected, I
believe. Also, you will want to smooth the border between the black and white
areas to simulate the slope of the threads.
Blaq!
Thanks Blaq, I'll give it a bash!!
[ continuation ]
factors, giving you a pointy screw rather than a straight one. Then you just
need to add a screw head as described.
Blaq!