Applying cross sections to a 3D file? How is it done?

jemhadar · Post by **jemhadar** » Wed Jun 15, 2011 2:05 am

Wanting to take a stab at building a master or one-of so now I have a 3d file of the subject and want to apply cross sections to the model and then print them out on paper then trace them onto plexiglass and build from there.
I seen this done on various modeling forums but no explanation on how EXACTLY it is done, what software to use? a step by step process would be the ideal answer and would help me out a great deal on my project which will benefit a great deal of people when completed.

You want new kits?? Please help me out on this issue.

I have the following software...

Blender
Google sketchup 8
3DS Max 9
Maya 2008
Wings 3D (really sucks)
AutoCAD 2010

em · Post by em » Wed Jun 15, 2011 2:36 am

Hey Jemhadar,

Use 3DS Max. You will need to use 2 modifiers (SLICE and CAP HOLES).

1) Center your pivot point around you model. Make sure it is exactly in the middle, unless it is asymmetrical.

2) Center your mesh around the origin (0,0,0).

3) Go to a left or right ortho view.

4) Turn on the grid (press "G" key). You can use it for reference.

5) Select your model, go to MODIFIER MODE. Under the the MODIFIER LIST, chose SLICE. Use this for where you need the cuts. Use the grid as reference. The SLICE will be centered around your pivot. You will have to move your SLICE PLANE to where your want your cross section.

Remember to collapse your mesh.

6) Delete the polys infront of this "cross section". Use the BORDER selction option and chose the open edge you just created. The selected edges will turn red.

7) Under the same MODIFIER LISTS, chose CAP HOLES or CAP within the EDIT BORDERS section of the panel.

8) A polygon will be created where the hole once was.

9) Now chose FRONT or BACK view for your viewport depending on which section you deleted.

10) Do a render.

11) Be sure to place a square or sphere next to the cross sections. You can use this to register the size of all the cross sections. You must do this because you can zoom in and out of your viewport and that will change the size of your cross sections.

12) Rinse and repeat.

PM me if you need more info.

em · Post by em » Wed Jun 15, 2011 2:49 am

Here is some Youtube videos

Shows some use of SLICE and CAP modifiers.

http://www.youtube.com/watch?v=IHVb_yw5wo0

G-man · Post by **G-man** » Wed Jun 15, 2011 5:19 pm

Too bad Autodesk hasn't put a version of this in Maya ( i'm a maya user, hate 3ds personally)...or have then and i just haven't taken the time to read about it yet?

George

oliver_s · Post by **oliver_s** » Thu Jun 16, 2011 3:26 am

Sketchup
http://blog.ponoko.com/2010/11/11/slice ... ercutting/

3DSMax
http://lab.visual-logic.com/skills-tech ... er-cutter/

http://mediastudio0910.files.wordpress. ... ing-3d.pdf

http://fbloop.files.wordpress.com/2009/ ... orial1.pdf

I use max and like the last method.

em · Post by em » Thu Jun 16, 2011 4:53 am

Hey Jemhadar,

Please use Oliver_s' 3DS Max recommendation (2nd choice) using the SECTION modifier. It is a much more elegant and efficient way to generate the desired cross sections. The technique I describe above is a brute force method.

If you use Max long enough, you will find that you can get the same results from at least 2-3 different techiniques. Just like real world modeling I suppose.

EM

PS - Thanks Oliver_s for the new trick. There are so many functions in Max that I never got around to playing with the SECTION modifier. I know there are a few CG modelers on this forum including me. I work in games. Do you?

Shizman · Post by **Shizman** » Thu Jun 16, 2011 2:22 pm

Thank you for this info! I've been trying to figure out the best way to do this for ages.

oliver_s · Post by **oliver_s** » Thu Jun 16, 2011 2:27 pm

No, I used to do a bit of animation but now don't really get the time to do it now. Barely get enough time to build models.

jemhadar · Post by **jemhadar** » Thu Jun 16, 2011 10:10 pm

Thanks for the great info!
Okay, I now have autocad 2010

I tried doing several methods.

I opened up sketchup and installed the slicer3 plugin, awesome tool!

but how to i change the scale for an example

I have a 3ds model of a nacelle, in sketchup I take the tape measure and its 21ft long, how to I make it to the length of my model and then slice it from that point?
21ft to 14" then slice then print is what I'M after or scale the whole entire model (ship) to my desired scale (length) and then slice?

em · Post by em » Thu Jun 16, 2011 11:03 pm

In whatever program you decide to use, go to your preference/custom settings or view settings. There should be an option somewhere to change your grid/units settings. Chose whatever is convenient for you. It would most likely be feet/fractional inches or metric. Sometimes the program will have "generic units" as a default. Chose one. Then import your model. Try to have the entire model in one file as opposed to multiple files.

Now create a box with the same dimensions as your subject matter. Then select all your mesh pieces and scale up or down. You may have to weld or group your meshes together if it is made from multiple pieces. Scale your mesh to fit the box you just created. Check the side, front, and top views for correct alignments. Make sure you are using uniform scaling so all dimensions stay in proportion.

As for cutting up the model, you can use the box you created for reference. When you create objects, in addition to size, you can also specify sub-divisions. Example, if you created a 100x100x100 ft box with
10 sub-divisions on each side, then each face will be 10x10 ft. Use the sub division lines on this reference box for your placing your slices.

Good luck. I hope you post your progress on the forum boards.

Shizman · Post by **Shizman** » Fri Jun 17, 2011 12:37 am

This should be sticky. Great info here.

jemhadar · Post by **jemhadar** » Fri Jun 17, 2011 4:07 am

I tried messing with this all night last night and no go

I'm trying to make cross sections, have them as a pdf to scale, print them out so I can make a 1/1400 and 1/650 subject (a Star Trek mystery model

)

anyone want to make this file for me?

I will redeem you with a free kit when its released because this is my intention is to make a kit cause we be needing more Star Trek models!

Styrofoam_Guy · Post by **Styrofoam_Guy** » Fri Jun 17, 2011 2:27 pm

Here is what I did to scratch by Serenity
http://www.alexkung1.com/scale/serenity/tut/tut.htm

I have also used this method to make a 3 ft Voyager
http://www.alexkung1.com/scale/voyager/vg.htm

I also made cross sections for a 1:350 Ent E (one Day) , 17.5" long Jembug (Scale?)

I started a 1:1000 Ascendant but lost interest for now.

jemhadar · Post by **jemhadar** » Fri Jun 17, 2011 7:43 pm

Alex, Hey I read those pages

I was trying to do the same thing with software I have but its proving to be above me.

Tankmodeler · Post by **Tankmodeler** » Fri Jun 17, 2011 9:57 pm

What file format do you have for the 3D model?

If it's a STP (Step) file, then I can import it into Solidworks & slice it any way you want. I can also scale it to anything you want as well.

Easy as pie. I can also import a number of other file formats, but they have to be vector files and not rendering files.

Paul

oliver_s · Post by **oliver_s** » Mon Jun 20, 2011 2:37 pm

Hi Alex, haven't heard from you since C5

Styrofoam_Guy · Post by **Styrofoam_Guy** » Wed Jun 22, 2011 12:49 am

Where do you think you were having problems?

jemhadar wrote:Alex, Hey I read those pages

I was trying to do the same thing with software I have but its proving to be above me.

Styrofoam_Guy · Post by **Styrofoam_Guy** » Wed Jun 22, 2011 12:50 am

Too many project so little time

How goes with you? It looks like I will be missing C6.

oliver_s wrote:Hi Alex, haven't heard from you since C5

oliver_s · Post by **oliver_s** » Wed Jun 22, 2011 12:23 pm

Looks like i'll be missing it too, work

MillenniumFalsehood · Post by **MillenniumFalsehood** » Sat Jul 16, 2011 9:19 pm

Don't know about the rest (and I'm a rather late addition to this party), but I always see if it can be opened in Metasequoia. If it can, I slice it into sections using the Knife function, connect all the points with faces, then deleting everything between them. After that, I take all the new faces into a program called Pepakura Designer and position them on 8.5"x11" paper and print them.

Very easy, very fast, stupid-cheap (Meta is free and Pepa has a free version that doesn't allow saves, but every other function is available).