Have you ever created a nice, smooth, flowing, perfectly fine
object in Ray Dream (such as a horse blanket, custom-fitted to the Poser
horse), but when you converted it to an obj file, it turned into a chunky,
lopsided, pyramidal shape? I hate when that happens! (Sadly,
I don't have any pictures of it to show you.)
If you haven't had this problem, have you noticed that your converted FreeForm object tears at the seams in Poser? Man, I hate that, too!
So here is my method I have devised to avoid these headaches.
(Note! I have updated and improved this proceedure. Click here to see Version 2.)
If you read the manual, it will tell you that when you convert to a MeshForm object, "This conversion can alter the object's appearance."
Here is a not-so-extreme example., seen in wireframe mode. On the left is a FreeForm object, made up of about 7 cross sections. On the right is the same object converted the the MFM. You can see right away that the wireframe of the FreeForm object has more wires than the Mesh version. You can adjust this when you "Jump in a New Modeller" by cranking up the fidelity slider. You can't really adjust it when you export to OBJ format.
The main difference between the FreeForm objects and the MeshForm objects is, the FFs can use bezier curves to define their cross sections, their extrusion paths, and even their envelopes. The MFs are limited to using only straight lines. Each curve in your FF object has to be reduced to a bunch of straight lines. This is where the loss in shape fidelity occurs.
Here is my base FF object. Notice I have avoided using an envelope to shape it, because I knew that would lead to conversion complications. But don't worry, you can still use envelopes with this method. :) This is the same object depicted above, with it's MFM counterpart.
Here is the same object, but I have added cross sections. The cross sections (x-secs in my vernacular) give the MFM something to hang points on when it is doing the conversion. You can see in the FF vs MFM pic above that the MFM only has 'cross sections' where the original object does, even though the FF version has more in it's wireframe mode. (Especially note the tail section -- the left end.)
The more x-secs you add, the better your conversion fidelity will be. You can also control the mesh density. More cross sections equals more polygon divisions. Here is the quick and easy way to add the x-secs:
First, create your FF object as you normally would: one cross section, an envelope, whatever. When you are done shaping it, select the first x-sec and hit Section:Create New. This will put a new x-sec on the object's endpoint, or any point you have added in the extrusion path or envelope. (Note: if you have added intermediary points, create a section for each by moving to the previous section and hitting Create New.) If you are new to this, or think you may want to edit your object's shape later, it's best to jump out now and work on a duplicate of your object in the following steps.
Second: Go to the next-to-the-last section of your object (use: Section:
Go To, and also note what number it is). Now hit Section: Create Multiple.
This will add sections between points (and, incidentally, add points,
which is why the resultant object will be harder to edit if you need to change
it later). How many you want to add depends on how far it is to the
next section, and how dense you want the mesh to be on this part of your
object. Three is a good minimum. For average density, I try to
do about one each grid line (I have mine set to 1"... also, view this operation
from the top or side, so you can see what you're doing).
After this operation, the FF modeller will kindly (and annoyingly) send you back to section 1. Use Go To again to go to the section before the one you first picked. (I go backwards, because if you add sections from the front, you will constantly be changing the section number of your main x-secs. Trust me, it's easier this way.) Create Multiple, etc etc.
Note: if you have a very curvy envelope and/or extrusion path, the sections created may mess it up and create unsightly folds and kinks. If this occurs, Undo, then create only one multiple x-sec. Adjust the distortion (if any), then keep sub-dividing this area with multiple x-secs of one.
And here it is, the conversion of the FF object with extra cross sections. MUCH closer to a 1:1 fidelity!
Another thing you can do to avoid messy conversions is try to use straight lines everywhere. To build the x-sec, in the extrusion path, on the envelopes..... Yes, it is more of a pain, especially when you are trying to make curvy objects. But do try to use them as often as you can. You can draw your x-sec with a bunch of little dots from the pen tool, rather than clicking and dragging a few points with long handles.
I like to use CorelDraw to make this automatic (and better looking!) Here's how:
I draw my cross section the way I want it, with the normal number
of nodes. (As on the left). Then I select all the nodes, and
hit the add button a few times. This creates nodes exactly halfway
between the existing ones. When I have a bunch, I then hit "To Line"
to remove any curve handles it may have.
Each node will also give the MFM something to hang its vertices on. It would likely try to add more points on my curvy shape... but who knows where or how many, and how distorted my cross section will end up? Now I'm in complete control! :)
Here's another nifty trick you can do when creating your x-secs in 'Draw. First, make all your sections with the same number of nodes, in the same drawing order (clockwise or counter-clockwise). I usually do this by duplicating my shape and then just reshaping it. If you have many cross sections that go through vast shape changes, you can get a 'preview' of how your 3D shape will look. Line up your shapes in a row, about the same distance apart that you plan your extrusion path points to be. Select the first and second shape, and blend with 20 steps. Select the second and third shape, blend... and keep going into a big, complex multi part blend. If you leave a pen outline on your shapes, you will get a quickie look at how the contours of your 3D object will go.
Save each x-sec individually (and remember RDD only uses version 4 or 3 CDRs). Then, when you create your FF object, import the first as an x-sec. It may be too large, and upside down... you can scale and rotate it into position. Place your other x-sec points on the path, then, with the first x-sec selected, Create New. Jump to the new one, select all and delete. Then import your second 'Draw shape, and so on.
is my fish x-sec in place, and everything set up ready to convert. The
envelope has all straight lines (except the very last node, where I rounded
the tail). The extrusion path is mostly straight, except at the head
part... Hint: don't do this. :) Keep the path straight, if you
are making a straight object. I bent the path to get a slope on the
chin part of the fish's head, and it turned out pretty badly. First,
the multiple x-secs between the first and second caused distortions because
of the bending. Then the envelope got a little kinked out of shape.
I would have been better off leaving it straight, then grabbing the
x-sec in the MFM and rotating it into position.
Also note that you can control the shape's curving even on a straight extrusion path, by moving the x-secs around on their plane. By default, the x-secs are centered on the path. Here, I could've moved the first x-sec up or down, instead of dragging the extrusion path endpoint up and down. Come to think of it.. If I had lined up all the x-secs so the bottoms were in a row, I wouldn't need the envelope to create the flat-bottomed, rounded top silhouette.
Note: if your x-secs all have the same number of nodes, you can also set each section's options to skin "point to point." This will help avoid some weird triangulations and semi-subdividing that can happen at particularly curvy sections of your model. Make sure you do this when you have all your main x-secs, but before you Create Multiple between them!
So in summary, remember that the MFM only uses straight lines, but you do have a choice on who decides how many and where the straight lines are: you, or RDD! :)
Now click here to see Version 2.