Curved Decks- How to draw band/rim joist ??

[taoist]

Designing a deck that has a curved portion.

I drew rectangle then ellipse and add surface to achieve desired shape.

I want to offset this shape the thickness of the rim/band joist.

Then I want to have only the perimeter rim/band joist showing not 2 polygons.

I will then extrude this to represent my rim/band joist then use the floor joist from Poly tool.

Think of a wall 2" wide but that matches the shape of the deck.

Tried using walls from shape but floor joist from poly tool does not work.

Floor joist from poly tool will not draw the rim joist correctly (all out of whack) for the curved portion.

Hope this makes sense.

[CipesDesign]

taoist, use the object you have to create a 1" wide band in top/plan view, then extrude that, or use it to create a Floor. One question: how will it actually get built? Will it be a true curve (made from bent steel, or ??), or will it be segmented? Often the solution for how to draw/model it is based on the real materials and techniques that will be used when it gets built...

[taoist]

Peter,

Thanks for the reply.

Trying to figure this out as I have never had to do this before.

Good learning process.

How do you suggest to create the rim/band, offset tool?

That would create 2 polygons.

That is not what I want.

Extruding or floor command is the easy part.

Floor is just and extrude.

I created the shape and extrude.

Tried the Shell tool, set to inside, depth of 1.5"

Leaves the polygon shape showing at the bottom.

In other words, did not cut all the way through.

Would be constructed of pressure treated wood.

Update: I used the offset tool using offset and duplicate.

Selected both polygons, clip surface, moved the remaining polygon.

Extrude, shows perfectly.

Used joists from polygon tool, shows the butt ends of 2 joists in the center area of the curved portion.

Still not working correctly.

Will keep trying.

The joists from polygon works fine.

See image of shape. Just want perimeter of shape 1-1/2" thick, 10" tall or deep. Think 2x10 rim/band joist

Edited July 27, 2013 by taoist

[mike m oz]

Taoist you can obtain a 3D rim by selecting both the top and bottom faces and then using the Shell tool. With the Shell tool active select the bottom face first using the Option key modifier and then add the top face to the selection set by holding down the Shift key. Once you have both faces selected confirm the Shell operation by clicking on the green checkmark icon.

[taoist]

Mike,

Thanks.

Will do that.

Makes sense.

I discovered that if I use clip surface as I stated earlier to obtain the rim/band joist, and leave it in 2D (non extrude) and use the joist form polygon tool, it still will not frame it.

I wonder if it is because it is a "hollow" polygon.

Edited July 27, 2013 by taoist

[taoist]

Update #2:

Joist from poly tool will not frame correctly either the solid polygon or the "hollow" polygon.

To create the "hollow" Polygon in 2D

create shape - draw rectangle & circle, add surface

offset & duplicate - to get rim/band width

extrude - to depth of joist or deeper

see image

create joists manually or use joist tool

duplicate array - to create joist set

adjust the joists as needed to meet the curved portion of the deck

Would be nice to know how to angle cut the intersection of the joists to the curve.

Deckworks Plugin from Trex makes it look so easy.

Update:

I discovered the 3D Powerpack.

Use the Stitch and Trim command.

Select the joist(s) then the rim (shape)

After running the command, select the parts of the joists you do not want then delete.

Advantage over Split Tool is you do not have to draw the "split" line.

Command should delete these automatically, IMO.

I noticed that it trims to the outer face of the rim/band joist.

Wonder if that is because I created the shape and then offset and duplicated to the inside.

I will try the reverse.

Edited July 27, 2013 by taoist

[Kevin McAllister]

Interesting problem. I model this sort of stuff all the time. Ironically I didn't know there was a joist tool. I tried it and it failed as you said. Attached is how I would do it. Extrude for the top, extrude for the perimeter and solid intersection for the joists. The reason I like the solid intersection is because you can move the joists around later and when you exit after editing they are properly trimmed again.

Note my duplicate preferences are set to duplicate in place which makes all of the polygons/extrudes quick to create.

If you need joist counts etc. this may not be your method since there is no way to "ungroup" them.

Kevin

[taoist]

Kevin,

Thanks for the reply.

Will examine your drawing.

Did not know about Solid Intersection.

Joist tool I believe was a Legacy Tool.

Use Framing member tool in Details Tool Set.

I assume when say top you mean decking.

When you say use solid intersect for joists, do you mean draw the shape, extrude and duplicate array?

Will try and see if solid intersection idea would work for this to constrain decking to shape with overhang.

Edited July 27, 2013 by taoist

[taoist]

Kevin,

Could you list a step by step how you did yours?

I am having trouble getting this to work.

Receive this error message.

See image.

[Kevin McAllister]

Sure can.

1) Using the offset tool I created a 2d polygon of the interior shape that holds the framing.

2) I then extruded the polygon to create a 3D shape that bounds the entire volume that will contain the framing.

3) I created a rectangle to use as a "joist" making sure it was longer than needed and duplicated it using the Move by Points tool.

4) I adjusted the spacing of the "joists" to get the appropriate spacing using the Align/Distribute command and a few manual moves.

5) I selected all of the "joist" rectangles and extruded them all together.

6) In front view I made sure the extruded group of "joists" and the extrude representing the framing volume were aligned.

7) With both extrudes selected I ran the Intersect Solids command.

You can double click on the Solid Intersection in my file to see the individual pieces.

This method would work great for making the shape of your top deck.

Kevin

[taoist]

Sure can.

1) Using the offset tool I created a 2d polygon of the interior shape that holds the framing.

2) I then extruded the polygon to create a 3D shape that bounds the entire volume that will contain the framing.

3) I created a rectangle to use as a "joist" making sure it was longer than needed and duplicated it using the Move by Points tool.

4) I adjusted the spacing of the "joists" to get the appropriate spacing using the Align/Distribute command and a few manual moves.

5) I selected all of the "joist" rectangles and extruded them all together.

6) In front view I made sure the extruded group of "joists" and the extrude representing the framing volume were aligned.

7) With both extrudes selected I ran the Intersect Solids command.

You can double click on the Solid Intersection in my file to see the individual pieces.

This method would work great for making the shape of your top deck.

Kevin

Kevin,

Thank you for the reply.

1) I did the same

2) Did the same

3) Did the same. Used duplicate array. Can't we use the Move by points tool to duplicate by said spacing?

4) Did not seem to need to do

5) Did the same

6) Are the joists touching the frame or are they vertically in-line?

7)From what I can determine, the two solid must be intersecting not just touching each other.

When I use the Intersect Solids command, it essentially wipes out everything.

I will try your method.

Update:

See images

one shows the joists and shape frame

one shows the result of Intersect Solids

The joists are vertically aligned to the shape

What am I not doing correctly?

Edited July 27, 2013 by taoist

[bcd]

On a side note - have you thought to use a three arc semi-ellipsish rather than an true semi-ellipse for this?

It provides a pretty decent approximation to a true ellipse and is easier to dimension, setout and construct.

[Gytis]

You're not doing step 2 of Kevin's instructions.

2) I then extruded the polygon to create a 3D shape that bounds the entire volume that will contain the framing.

First model the entire volume inside of the rim joist. Then when you Intersect Solids with the field joists you should end up with them trimmed as needed. Then add rim joist.

It's how I understand it anyway.

[taoist]

You're not doing step 2 of Kevin's instructions.

2) I then extruded the polygon to create a 3D shape that bounds the entire volume that will contain the framing.

First model the entire volume inside of the rim joist. Then when you Intersect Solids with the field joists you should end up with them trimmed as needed. Then add rim joist.

It's how I understand it anyway.

Thanks,

Appreciate the input.

I tried it and it works.

Now to see, if i make adjustments, if the joists trim accordingly.

The joists are part of the "solid" polygon, not the rim shape.

[Kevin McAllister]

Gytis is correct. My instructions are for creating the solid intersection for the framing only. I didn't detail how to create the rim joist. The easy way to fix things is -

- ungroup your result, which gives you back your joist extrude and rim joist extrude

- duplicate your rim joist extrude

- edit the duplicate. Create a rectangle that extends beyond the boundaries of the existing shape. Send the rectangle to the back. Select your original rim joist shape and the new rectangle. Subtract surfaces. Delete any remnants of the rectangle outside your rim joist boundary and the rim joist shape. You should now have a polygon the shape on the interior volume where the joists will live. Exit the edit mode for the extrude.

- you should now have the correct two pieces to perform a solid intersection. Select your joist extrude and the new extrude we just created. Intersect solids.

Kevin

[taoist]

Kevin,

I examined your drawing closer.

You have 3 separate extrudes

1) shape polygon 1-1/2" extrude this explains the shape cover or deck surface if you will. This is one of the solids used with the intersect solids command. The other solid is the joists.

2) rim joist extrude, 9-1/2"

3) rectangle extrude 9-1/2"

All makes sense now.

I really appreciate everyone's help in getting me up to speed.