Cross sections not lofting properly.

[craig809]

I am working on creating a male mold for a canoe. I first designed the cross sections for the canoe and then began converting them to the mold cross sections. When I try to loft the cross sections I have converted so far, they all loft as I intended until I get to the rear of the canoe (sketch 8). The issue typically arises in gunwale section (the part that appears to be a notch in the sides). Everytime I loft, one of the gunwales splits/twists in an undesired fashion (in the image below the right gunwale is incorrectly twisted).

I do not understand why this is happening for a few reason:

1. The canoe cross sections lofted as planned, and I only added simple boxy shapes to those cross sections.

2. Each cross section is symmetrical (or at least from what I can tell they are).

3. The cross sections that are lofting improperly all have the same number of segments and are in very similar shapes.

If anyone knows or has an idea of what may be wrong, I would greatly appreciate the help.

I have attached the file of the cross sections and another file of an improper loft.

[JDMather · Accepted solution]

Is this your first Inventor project?  If so, you should start with something easier.

Keep your sketches simple - it looks like you are trying to do too many features in one profile.

Get a basic (simple) shape and then add addtional features.

Fully constrain your sketches.

Use Extrude rather than Loft for any profiles that don't change.

It looks to me like you are doing too much work based on inexperience - I recommend you go through these before attempting this project.

http://home.pct.edu/~jmather/SkillsUSA%20University.pdf
http://inventortrenches.blogspot.com/p/inventor-tutorials.html
http://wikihelp.autodesk.com/enu?adskContextId=HELP_TUTORIALS&language=ENU&release=2014&product=Inve...

Also, you can dramatically reduce file size for attaching here by following these steps.

Find the red End of Part marker in the browser.
(End of Folded on sheet metal parts EOF)
Drag the red EOP to the top of the browser hiding all features.

Save the file with the EOP in a rolled up state.

Right click on the file name and select Send to Compressed (zipped) Folder.

Attach the resulting *.zip file here.

[craig809]

Thank you for your feedback. This is my first project with Inventor, with my only experience coming from watching YouTube videos and playing around with the software. I am doing this project out of necessity, not out of choice. I am on a student team where we create a concrete canoe and race it against other schools, and part of that is making a mold. Unfortunately, according to the competition rules and the mold making company we have to design the canoe/mold in 3D. No one else on the team has any 3D modeling experience. Since I have a decent amount of experience with 2D modeling I thought I would give it a try.

Unfortunately, I do not have much time to get this complete. I am already two weeks behind schedule and if I don't complete this within the next two days, we will not have time to have the mold made and have our concrete cure before competition.

I will work through and try to simplify the cross sections and will take a look at the links you posted.

Thank you again!

[JDMather]

Search on concrete canoe design here.

Another student was working on something similar a couple of months ago and you might be able to see how the profiles were simplified in that design.