Hey Guys,

I'm working on trying to take my 3D modeling skills to the next level and for the life of me can't figure out the best way to do something. I've been working on this for the past 24 hours, trying to figure out the best way to do model the attached into a solid. I've extracted some meshes from a program (cgf files) then converted them to obj files. From there (through lots of trial and error) I've found the best way is to use a converter I'd found on here for converting obj files into what ends up being polygon meshes when loaded into MoI.

From there, I just go into the "mesh", create surfaces, join all surfaces, and end up with a joined surface and this is where I get stuck. From there, I can't seem to generate a solid, even when I close up the model as best I can. I've tried a suggestion I found here in shrinking the model down to see if that will help close things up, but that didn't work.

I'm trying to mull through the best way to create a solid in MoI from these imported obj mesh files.

The attached file has two joined surfaces, the bottom one I've tried to close up in an attempt to make it a solid (unsuccessfully) the top I haven't done much with other than create the planar surfaces and join them.

Ultimately, I'm wondering if this is even the best way to go about this? I've tried just using shapes to sweep or loft to create these complex geometries, but I've been unsuccessful up until now. So my questions are - is pulling the meshes into MoI and using them as some sort of base to create planar surfaces the best way to do this? How would you go about modeling the shape in the attached file? Open to any and all suggestions on how I can create shapes such as this in MoI a bit easier?

Attached is where I stand on modeling this section of cockpit (which is part of a larger model with a lot more complex shapes).

Thanks,

Ryan.

It looks like you have many polys not terminating properly in your model. Don't know if that's part of the original model or an artifact of the OBJ import. If you can, use the "select naked edges" script
http://www.kuto.ch/moi3d-shortcuts/
to find the problem areas when trying to create a solid. This will show you what else needs to be 'sewn up' in order for the mesh to be a solid. See below for 'naked edges'

OK, so I've installed that script and run it - so now I at least know where my problem is.

Any recommendation on how to easily close them up? I know Rhino has some commands to fill gaps and clean up naked edges?

Thanks for the help!

Hi Ryan, this is not really a great way to build a model in MoI, NURBS modelers do not expect to be dealing with a whole bunch of separate little facet pieces especially ones that are only at slight angles to one another.

So to get good quality geometry in MoI you would likely need to reconstruct much of this rather than trying to use the model directly as-is, as far as NURBS geometry goes this type of faceted structure is not a good type of geometry to have, if you want to do further operations on it such as filleting especially.

But really the main problem with naked edges seems to be from duplicated faces, there are several facets that are stacked up directly on top of each other with some of their edges joined to their duplicates. The duplicates will need to be removed first before you will be able to make a clean joined structure.

To do that, start by selecting and hiding the top part which is a separate piece, work on only one visible piece at a time. Then take the bottom piece and run Edit > Separate on it to break it into individual surfaces. Go around the model and one by one select a face and delete it and see if you can see through the model or not. If you don't see any change after the delete you just deleted a duplicate and try again on the same spot to see if there is another duplicate as well. If you see through the model then there was not a duplicate there and do undo and go on to the next face.

Or the other thing you can do is to do one click on each face to build up a selection of just single faces and then invert the selection and delete the remaining ones. This may be a bit tricky since the display can get confused between which of the duplicates is showing on any given screen draw.

At any rate it's the stacked up duplicate faces that is making it not be joined up properly.

- Michael

Hey Michael,

Yeah, I got the top piece done, but in the end realize that if I'm going to work with meshes, it's better to work in Maya or some non-NURBS based tool. I'm not as proficient in mesh based modeling as I have done most of my modeling in MoI over the past few years.

So, maybe a better question is - any recommendation on how to model shapes like this? Where I really struggle is modeling things that has angular planes where the plane has an X,Y, Z component. I'm great at doing things where I'm boolean cutting objects in one plane, but when I have to model something where the plane doesn't fall cleanly in two coordinate planes I get tripped up. Thats where I thought perhaps trying to do things more with sweeps/lofts may make things easier, but I haven't mastered them as of yet.

Thanks again for any help or guidance you can offer.

Ryan.

Hi Ryan, well there are a few different ways you can approach angled planes. One would be to draw some lines in a 2D view like the top view and then move one of the lines vertically in Z until you reach your desired angle and then build a surface between them with loft.

It's also possible to draw an angled plane directly all in one shot by using the Draw solid > Plane > 3pts command, place the first 2 points at the bottom edge of the plane and for the 3rd point go to the 3D view and drag a construction line up vertically in the z direction and then you can snap onto that construction line to give your plane an angled elevation. That looks something like this:


You can also start with an axis aligned plane and then do repeated rotations in different 2D views to get it to different angles.


Probably a starting point would be to start with one 2D profile curve like this:



Extrude that out to make a base shape that has some element of the final shape you want, like in this case it has the side profile:




Then create an angled cutting plane using one of the methods described above, in this case I used a combination of Draw solid > Plane > 3pt to make an angled plane to start with, just snapping it on to the top edge of the solid rather than using a construction line to make something close to the desired angle, then adjusted it slightly by rotating it using the edit frame rotation grip in the top and front views to tweak it slightly, and scaled it a little bit using the edit frame too. So once you have it at your desired angle like this:



Then you mirror the cutting plane, then select the base piece and run Construct > Boolean > Difference and use the planes as the cutting objects. That will slice the base object up into pieces like this:



Then delete the unwanted pieces to leave this part:



- Michael

Then a way to form your inset panel is to select your main shape and run Construct > Offset on it with the "flip" option set to make a shrunken down version of it that is contained inside the center of the original.

Then draw in additional profile curves in the side view:





Select both the body pieces (the main one, and the shrunken down interior one created by offset), and run Edit > Trim and use those curve as the cutting objects.

Then delete the inner portion of the outside body:




And delete the outside portion of the inner area:





Then select pairs of edges and run Construct > Loft to make connecting surfaces.

If you want the connecting pieces to run at some other angle then you may want to trim each piece to slightly different outlines, you would probably use Construct > Offset on the cutting curves to make an offset curve and then use one set for trimming the outside body and the other offset curves for trimming the interior piece.

Hope this helps!

- Michael

Michael,

Yes, it definitely does! Every time I've come back to the forums over the years, you've always been super helpful!!!!

It's interesting how there are so many ways to do things in MoI (some just seem to be less intensive than others in terms of the work involved). I spent some time tonight creating shapes, using sweep and rails to get pretty close. Your method seems to achieve the same results with less time, so it's probably the better route to go.

Thanks again!!!

Ryan.