Tunnel Portals?

John,

Have you seen the ones Scenic Express makes?

https://www.sceneryexpress.com...stems/products/1076/

John

@Craftech posted:

John,

Have you seen the ones Scenic Express makes?

https://www.sceneryexpress.com...stems/products/1076/

John

Sure, but the whole point was to print them since I have the printer.   This is the 3D Printing forum, right?

I know that one of the questions I have is would you make them taller? I know that the GG1 will not go through any normal tunnel portal as they are too short for the pantographs if extended. While I don't know if that is something that happened in the real world, I have seen people struggle with that issue when it comes to them running a GG1 through their tunnel.

@Dave NYC Hudson PRR K4 posted:

I know that one of the questions I have is would you make them taller? I know that the GG1 will not go through any normal tunnel portal as they are too short for the pantographs if extended. While I don't know if that is something that happened in the real world, I have seen people struggle with that issue when it comes to them running a GG1 through their tunnel.

Not for my layout, my second level gives me around 5.25" from the railhead on the main level, that's too slim for the GG1 to have the pans up.  That being the case, it's pointless to have the tunnel portals taller...  The pans should be riding on catenary, so if I run those GG1's, I just leave the pans down.

I found some tunnel portals on some of the 3D model sites, I scaled up an HO set, cut them in half to be able to print them on the printer, and the first half is printing.

If the first one works out, I'll print two left halves and two right halves at a time, just can't print the complete portal at one clip because it's wider than the 220mm max for my printer.

I found some more ornate stone ones as well, I may print those next.

I think too John, doesn't the catenary when running into tunnels come down lower to fit into the tunnel? I want to say that I have seen that posted somewhere, but I can't recall. Of course, that doesn't work for the VL one as they do their own thing. Oops. No GG1's for me doing that business. I guess it depends on the layout, eh?

@gunrunnerjohn posted:

Sure, but the whole point was to print them since I have the printer.   This is the 3D Printing forum, right?

This is the running column of posts on the right side of the page.  Didn't dig any further.

But a 3D printed tunnel portal sounds like a great project.  Hopefully someone creates one. 

John

Well, I'm half-way there...  I'm printing the right half now.

Looks like I can just 3D print them.   I'll print a few of these, and then try some of the rough stone versions, see which I like best.

John, If you decide to explore options other than 3D printing, I have done some tunnel portals using blue insulation foam.

random stone pattern for each arch

@AlanRail posted:

random stone pattern for each arch

This looks like a great use of Grasshopper.  Do you have your approach documented anywhere beyond that screenshot?  I've got a bit of other work before I get around to tunnel portals, but I'd love to use Rhino + 3d printing when I get there.  I imagine this could be used to quickly pump out a large number of options for people that don't have access to the software as well.

@AlanRail posted:

random stone pattern for each arch

Well, hello there. That looks amazing.

@AlanRail posted:

random stone pattern for each arch

Not sure I'm quite ready to try and recreate that.  If it shows up in the 3D library, I might try to print it.

yes it was made using Grasshopper.  real easy.  i created a random surface in Grasshopper then using Rhino to split the surface into my various stone shapes that were then applied to each of the stone faces. each face cut was different as i split the surface at different parts of the generated surface.

the  Grasshopper flow was found in a web search for Rhino random surfaces that i modified.

OK, pardon my ignorance, but what is GRASSHOPPER and what is RHINO? Are these 3D printing programs?

Gerry

Here's one... use Tree 'Slim' ...may add a couple of Gas Lanterns to it.

@gmorlitz posted:

OK, pardon my ignorance, but what is GRASSHOPPER and what is RHINO? Are these 3D printing programs?

Gerry

Grasshopper is visual programming plugin for Rhino, which is a 3d modeler.  So it is sort of one step upstream of the 3d printing part.  The potential here is that generating the geometry can be highly automated and customized.  Rhino isn't free unfortunately, but it is IMO the most capable modeling tool for the price, which is somewhere in the neighborhood of $800 for a single perpetual license.

I'd be happy to upload a variety of options for those that don't have access to the tool when I get to this phase of my project.  Perhaps @AlanRail would be willing to upload a few as well?  They do look pretty slick.

When scaling an object like a tunnel portal it is not necessary to scale all dimensions equally.  For example, if you needed a portal for a track on a curve where the width needs to be wider all you need to do is increase the scaling in the width direction accordingly.  It will increase the width of all of the portal.

Jan

Rhino 8 is a 3D surface modeling program as Pat said. In that regard it is different from most 3D modeling programs that model solids instead of surfaces.

A set of surfaces that are arranged in a way to create a solid form is then a closed solid. Like the 6 surfaces of a cube. What Rhino does is allow you to separate the surfaces of the cube. Then use the surface to create other surfaces or solids that identically match the surface. A cube is fairly simple example of this approach to 3D modeling.

In this way a 2D surface can be created and then extruded into a solid 3D object. This allows me to match parts of a photograph in a 2D outline and then extrude the outline into a 3D object to print.

Grasshopper was a separate plug-in that is now incorporated into Rhino 8. Grasshopper allows you to create graphical algorithms in an editor that is tightly integrated with Rhino’s 3-D modeling tools.  Grasshopper requires no knowledge of programming or scripting, but still allows designers to build form generators. The result as you can see is the random stone faces.

@Dennis-LaRock posted:

Here's one... use Tree 'Slim' ...may add a couple of Gas Lanterns to it.

@Dennis-LaRock This a cool portal but will it allow stack cars and auto carriers through?

@Shawn_Chronister posted:

@Dennis-LaRock This a cool portal but will it allow stack cars and auto carriers through?

Shawn,

You can size it for a tad better than 7" clearance on most printers... add foundation Blocks for additional height.   Printed at 245x220mm should give one approximately 7"x 5.25" clearance.

Nice Dennis, I'll have to give that a try.

@gunrunnerjohn posted:

Nice Dennis, I'll have to give that a try.

Here's the 248x230 version... and a shot of the supports: Tree, 'Slim'

Cool, did you try it in the other orientation right-side up?

I am printing it flat with slim tree supports.

Here it is completed.

Shawn, too big for my build area laying flat.

@gunrunnerjohn posted:

Shawn, too big for my build area laying flat.

You have a have a K1 correct 220x220.

I printed that on 180 x180. I did not change the demension to make it bigger you have 40 more mm how is it not big enough.

Because it's 248mm high, laying flat that exceeds my 220mm build plate!

I thought the pantographs on a GG-1 compressed when going into a short tunnel portal. The cantenary is just closer to the top of the GG-1 in that situation.

You can change the dimensions... 248x230 is a diagonal print on the 220x220x250 build plate ...for the 'one-piece' build and has to be printed vertically to get the 7"x5.25" clearance.  Nothing wrong with laying it down.   I have it split into component parts as well... so, one could turn it into a monster, if desired.

Laying it down at the size it is didn't work, I didn't resize it.

@gunrunnerjohn posted:

Shawn, too big for my build area laying flat.

Sorry I missed that he uploaded a bigger file.