I am trying to model a bike frame. Tried spline modeling, works really well. Except when trying to merge two surfaces, or tubes together. The tubes on the bike don’t just meet but merge, it’s like a tube meets a tube, but then they meld together.

Hi mike.
Post an image of what you think the problem is, and explain the result you’re aiming for. For now what i can say is that you should try poly modeling.

Try renderable Splines, or a Sweep. Both work quite well in that sort of situation.

Max 4.2 through 2012 (SP2+SAP).
XP-64 (SP2)
NVidia 9800GTX-512 (Driver 266.58).
Core 2 Quad Q6600 2.4GHz, 8Gb Ram, DX9.0c.

At the risk of self-plagiarism, I offer this, with consent of the author.

How to connect a wing to fuselage with a smooth seam:

The main idea is to have an equal number of vertices on the border of one element as on the other element you want to Bridge. The same holds for the Connect compound object.

1. For the fuselage create a Cylinder, convert to an Editable Poly and deleted the end caps.
2. For the wing make another cylinder convert to an Editable Poly and scale it to a rough wing shape. Each cylinder as 18 sides. (I rotated my fuselage cylinder so I would have a clean mid-line.)
3. On the inside of the wing, the part that faces the fuselage, delete the end cap.
4. On the fuselage, select all the polygons on the side away from the wing and delete.
5. Use the Attach command in the Edit Geometry rollout to attach the wing object.
6. Go to Border sub-object and select the border that is on the open end of the wing facing the fuselage.
7. In the Edit Borders rollout, click on Create Shape From Selection. Important: in the Create Shape dialog, set the Shape Type to Linear (otherwise you will wind up with excess vertices).
8. Exit sub-object mode of the airplane (fuselage and wing) and in the Select by Name dialog, choose your new Shape. To make the shape easier to work with, right-click in a viewport, choose Object Properties and turn on Vertex Ticks in the Display Properties.
9. At the vertex sub-object level, Scale (on Selection Center) the shape larger and move it upward slightly. This is to be used as a guide for cutting polygons in the fuselage.

This is where the differences in my example and your work will really stand out. But the basic concept is the same: Cut polygons and move vertices as needed.

10. Select the airplane and click the Cut tool. Using the Shape as a guide, cut the polygons in the fuselage. Notice the extra cuts necessary on the polygons at the leading a trailing edges of the wing. For this model, I made some additional cuts so that there would be corresponding vertices on the fuselage and wing.
11. Go to Polygon sub-object mode, select and delete all the polygons inside the area of the fuselage where the Bridge will occur.
12. Go to Border sub-object mode, select the border on the inside of the wing, and at the hole created in Step 11.
13. Click the Settings for Bridge. I used 4 Segments and a Taper of -.40. More adjustments are necessary. Click OK to accept the settings.
14. Go to Edge sub-object. In the Top or Left viewport (for me) select one edge of one of the “rings” created by the Bridge. Click the Loop button in the Selection rollout. Use the Scale and Move tools to adjust as needed. Repeat on the other “rings” to create a smooth transition between the wing and fuselage. (Practice required. Good time to Save As +)
15. Smoothing Groups. Go to Polygon sub-object mode. The “bridged” polys may still be selected. If not select any one. Scroll down in the Modifier panel to the Polygon: Smoothing Groups rollout. Click on a fuselage polygon and note its number. Also one for the wing. In my case, the wing and fuselage use number 4, and the bridge polys use number 1. A polygon may be assigned multiple numbers, but if it is to be “smoothed” with an adjacent polygon, they both must share a common number. In my case I made the bridge polys number 4 to match the wing and fuselage.
16. Exit sub-object mode. Apply a Symmetry modifier and adjust the Mirror Axis setting and position to create the other half of the fuselage and the other wing. Make sure Slice Along Mirror and Weld Seam are active. You do not want a gap in the seam, and little or no overlap. (Save As +) Convert to Editable Poly if desired.

Tim Wilbers [FA]

College of Arts and Sciences
Department of Visual Arts
University of Dayton
http://www.udayton.edu/
3ds Max: 7.5, 8, 9, 2008, 2009, 2010

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Or, for pipes of equal diameter:

1. Draw the basic shapes as one Spline object. Make sure there are two vertices at each T-intersection. In the image there are two vertices at each red vertex indicator.
2. Add a Sweep modifier set to the Circle and the diameter of the frame pipe. In the Sweep Parameters, check Union Intersections. Convert to Editable Poly.
3. Using Edge sub-object mode, range select all the edges at an intersection, then range de-select (ALT) the long edges on the pipes. Leave only the edges at the intersection.
4. Chamfer the edges using the Settings. Set the segments to make a smooth intersection.
5. Use Polygon sub-object and select all the polygons. In the Polygon Smoothing group (Modify panel) click on Auto Smooth. The default setting of 45 should work.

Tim Wilbers [FA]

College of Arts and Sciences
Department of Visual Arts
University of Dayton
http://www.udayton.edu/
3ds Max: 7.5, 8, 9, 2008, 2009, 2010

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Tim_Wilbers 29 October 2009 09:36 PM

2. Add a Sweep modifier set to the Circle and the diameter of the frame pipe. In the Sweep Parameters, check Union Intersections. Convert to Editable Poly.

This is really a great tip Tim.

E. K. Anna Hennequet [FA]

ekah 03 November 2009 11:51 AM

Tim_Wilbers 29 October 2009 09:36 PM

2. Add a Sweep modifier set to the Circle and the diameter of the frame pipe. In the Sweep Parameters, check Union Intersections. Convert to Editable Poly.

This is really a great tip Tim.

I’ve played around with this and realize that Union Intersections doesn’t work well with other shapes. But when used with Sweep modifier’s built-in Cylinder shape, or Circle or Ngon set to certain number of sides (4, 8, 12, 16, etc) it works really well.

Thanks again Tim. :)

E. K. Anna Hennequet [FA]

Well thank you. Much appreciated.

But, as Anna rightfully pointed out, some procedures work great for some applications, but fail miserably for others. Its always useful to understand the various approaches to solutions and modify and combine as necessary. Its the difference between following a recipe, and being a chef. (And I’m a long way from being a chef, but I might be able to help stir the pot.)

Tim Wilbers [FA]

College of Arts and Sciences
Department of Visual Arts
University of Dayton
http://www.udayton.edu/
3ds Max: 7.5, 8, 9, 2008, 2009, 2010

Tim, you’re a chef alright. And I love this recipe. :)

E. K. Anna Hennequet [FA]

Now, i´m really gonna have to try this spline recipe just to “chef” up my modeling skills a bit. I’m too stuck on poly modeling and often overlook these great solutions.

I just had dinner so I thought I would add some desert.

The pipes in the attached image were created from a Spline with a Sweep, with an Edit Poly on top. Vertices were edited to create the “joints”.
Viewing the movie reveals flow inside the pipes. These were created with clones of the original splines with a Sweep using a smaller Section.

Sweep has the same mapping properties as Loft.
Editing the vertices allows for the pipes to have different diameters and shapes, but still be one continuous element.

Maybe useful for the bike frame if the pipes need to be tapered.

Tim Wilbers [FA]

College of Arts and Sciences
Department of Visual Arts
University of Dayton
http://www.udayton.edu/
3ds Max: 7.5, 8, 9, 2008, 2009, 2010

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