# Modeling Diving Knife Tutorial

### STEP 3 – HANDLE

In this part naturally we will go through handle creation. Again, we will use the same approach. First, create a base form and then using various operations we will make details on that base object. So, lets get started. We will start tracing out the sections from Front viewport, then after we are finished, we will rotate it. First, I’d create a symmetry line. Then start working on one half, then it, if needed the parts of lines I don’t need, and then using command with Average Curves option on smooth out the transitions between curves.

Outlining the blueprints

Trim and with 3 units as radius lower straight line and outer curve:

Trim, Fillet,

Ok. Next we need to explain something. The two curves (one ellipse and one curve – yellow ones) are needed, but they also need to be trimmed and joined with the two curves that touch them. So, Copy (with InPlace option) these two, and hide for now.

Copy with InPlace option

We will trim the originals with two curves:

Trim

Now, using Match command match lower curves to the trimmed ones:

Match

Now, using Mirror, mirror all curves using that straight line as symmetry line:

Mirror

Now, we must Match the lines on the symmetry line, and for that we will use Average curves option in Match command, and when you’re done just use Join:

Section curves done!

Now, select all section curves and using we will start the rotation axis on one end of this symmetry line, and from Top viewport we will rotate by 90 degrees.

Rotate section curves

Using command move all the sections to their places using blueprints as reference.

Place section curves

After you have positioned all the sections the right way, we need to create two curves from Front viewport to define our shape. Use Mid and End points on section curves so your curve is touching them.

Rail curves

Using command make a surface out of these curves:

Base form

New, lets create another curve with command from front viewport following the curve on the blueprints:

You know what to do next. Trim the surface with the curve (from Front viewport).

Trim surface

Now, we need to explode this curve with command.

Explode this red curve

We will get four segments out of this one, and we need to adjust two bottom ones. Using command show the control points and move them so they touch the intersection with closed curve and edge of surface. So for that naturally you will need to have Int OSnap option ON.

Explode and match

Now, we need to one curve. We will split it with the surface:

curve to split

You will get two parts of that split curve:

Two curves we need next

Using InterpCrv command, we will create two curves. We will click just three times for each curve to define them. So for start we will click on the ends of two yellow lines and on the dot. We’ll do the same for the opposite side:

Two simple curves

Ok, you’ve created these, and now we need to create a curve out of surface edges. Click on the surface, and run command. Ok, now this curve needs to be split into two pieces:

Curve we need to split

We need to split the yellow curve with the red ones. So, select the yellow curve, and run Split command and click on the three red curves:

curves

Using that split curves, we will create a surface with NetworkSrf command and with the help of all yellow curves on the image below:

NetworkSrf

Now, you can Mirror that surface, and hide everything except those two. And turn on the blueprints layer again, we’ll need it now.

Hide everything

Now, trace the wavy curve from the blueprints and Copy it:

Wavy curves

Using upper curve, Trim the two surfaces:

Trim the surface

Now, using some OSnap and brain we will put one on the lower wavy curve:

Point on Intersection

Let me explain what just happened here. Since we know that Int OSnap option means cursor snapping on the intersection of two curves, those curves actually don’t have to intersect in 3D. Only in 2D. So, from Fron view, they seem to be intersecting, and placing a Point on that intersection in the Perspective viewport we will see where that point will be placed. It can be placed on either curve. So, by just slightly moving your mouse it will snap on one then on other curve. Then just click to create a Point on the wavy curve (this is all done from Front viewport, it is handy to have a perspective viewport ONLY visible so you can check on which curve the point will be created) After that, using that Point we will trim that wavy curve:

Trim

For the other end of that same curve we will do some trimming also with the curve which actually intersects our curve in 3D. So no problems there, just trim from Perspective viewport:

Trim the red part (click on the red side of the yellow curve)

Ok, now we will adjust that curve and move its end to the surface end. Using PointsOn command we will show the control points and move the last one:

Move control point

Ok, this isn’t really gonna be ok, because we need way smoother transition. Why the hell this happened? Well, as you noticed there is one more control point very close to the last control point. And that makes the curve like this. What we need to do now is delete that control point. Just select it and hit key.

That is one much nicer curve

Using InterpCrv we will create one more curve:

InterpCrv

When you create this curve, you will need to Match its ends to the edges of this blue surface. Just make sure you don’t have Average Curves option in Match command checked. Ok, now we need one more curve. But on the other side. We will use this yellow (on the image below) curve and split it with two surfaces:

This curve

Split with these two surfaces

This is what you will get. Note, this one yellow curve is actuall two curves, so you will need to Join them:

Curve

Ok, now using NetworkSrf command we wil create a surface between two curves we just created, edges of two surfaces and one “rail” curve.

NetworkSrf

Lets Join all surfaces now finally. Next step would be to close this surface into one solid. First lets go to the end of the handle, and using PlanarSrf select ALL edges on the back and create a surface:

PlanarSrf

Using command we will go to the other side of the handle end extrude a bit according to the blueprints. So if you have your blueprints layer turned off, turn it on.

Extrude

This extruded surface will be into four parts, you can Join those parts with rest of the handle surfaces.

Joined surfaces

Using DupFaceBorder command we will make a curve border out of inner surface of the blade: (it is possible you will get two rectangles one by the other, you can then just trim the mid line and join them, but I would suggest just using PolyLine command trace the Ends and corners on that Face)

After that, we need to Offset this rectangle by 1 unit. And then, using Rectangle command and Rounded option make a rectangle using this one:

Rounded rectangle

Now, why in the world we did rounded rectangle? Well, we will make a transition from handle which is pretty round to the blade back which is pretty sharp edged. That way we will get weird transition on the surfaces too. But if we have both sides a bit rounded there won’t be any sharp edges on the surface. Using DupBorder command on the handle surface we will get closed curve:

DupBorder

Now, isolate (aka hide everything else but) two curves. The one just made and the other one is rounded rectangle. Using command and OSnap End, Mid and Perp options create four lines starting from the rounded rectangle to the closed curve.

Lines

Using NetworkSrf command create a surface from these curves:

NetworkSrf

Now, Join all handle surfaces, and using command close it into one solid.

Closed solid

Using command make a round edge on the back of the handle with 0.8 units as radius:

FilletEdge

Next we will make top handle details. We will create one Line and then Copy it according to image below:

Lines

Now, using command we will project those lines onto the handle surface from Front viewport.

Next, with command make pipes out of projected curves. For the radius use 4units.

Pipes

Now we gotta end those pipes with spheres. With command make spheres centered on the ends of curves and use radius of 4 units.

Spheres

Ok, now that we got our spheres, we need to join them. But with command. Then, using command make holes:

Nice surface ðŸ˜€

We can now use FilletEdge to smooth the edges, but, and that is a big BUT, that doesn’t work every time. You can try, I did, and it didn’t work. But it is a good practice to try it first because you might get away with it and save some time. If it doesn’t work, then you are stuck with pipe method. That is, create a pipe through the edges, split the surface with this pipe, and using some surfacing command create a surface to fill that gap. So, lets first create pipes of radius 1unit. Don’t forget to click on ChainEdges option before selecting any edge because these edges are shattered in a bunch of them… You can try using Autochain option after that ChainEdges option. It is very handy too.

Pipes

Using Split command split our handle surface and delete pipes and the parts pipes split.

Holes

Using Blend command we will make a curve that connects two edges:

Curve

Ok, let me explain this last step. What you need to do is start Blend command, then click on Perpendicular, and then click on one edge (having Quad option in OSnap is good thing) and click on that edge where you find Quad snap. Next, again, click on Perpendicular, and then click on other edge, and there find where quad osnap is, and there click. Using DupBorder command you need to create curves out of edges:

red curves

Using Sweep2 command make some surfaces, and then join them:

Handle object

Lets make a hole in the handle for the string or something. Go in front viewport and create a circle with 5 units as radius. Offset that circle by 2 unit to inside (I moved it a bit from the edges):

Circles

Trim the surface with bigger circle:

Trim surface

Using create a surface out of two edges and one smaller circle:

Loft: use Normal settings

Join those surfaces, and using FilletEdge, fillet the edges with 0.8 unit as radius. Ok, now lets move a bit up, and make another detail. Select ellipse and Offset it (from Right viewport) by 1 units towards inside:

Offset

Extrude the red ellipse according to our blueprints:

Extrude

Ok, start Point command, and now using STrack in toolbar, and Quad and Int option in OSnap, hover over two quad points in Perspective viewport, and in Right viewport click on the intersection of two STrack lines.

Point

There is another way of doing this without STrack. Just using PlanarSrf create a surface, and with AreaCentroid on that planar surface the command will automatically create a Point in the center of that planar surface. Easy, huh? Now, move that point away, and offset the surface edge by 3 units.

Offset

Now, with Loft command make a surface out of Edge, Curve and Point. Please note, you will have to adjust the spacing between each to get smooth tip where the point is:

Loft

Join those two surfaces, and using FilletEdge fillet the edges with 0.8 as radius:

FilletEdge

Using Cap command just close this polysurface into one solid. Great, you are almost done. Almost. There is one last detail on this handle. Go to Front viewport and trace the curve according to the blueprints:

Curves

Ok, now you will need to Explode handle surfaces, and join only these. The rest you can hide:

Part of surface

Using Mirror command mirror that curve using horizontal line as mirror axis. And with Match command with Average Curves option checked.

Mirror

Using the same method with putting the Point on intersecting curves which are actually not intersecting in 3D we make a point on our curve. That point needs to be Mirrored:

Points

Trim the curve with Points, and create a Line between start and end of that Curve. Join curve and line.

Line

Using Offset, offset that curve towards inside by 1 unit:

Offset

Using Project, project these two curves from Front viewport.

Project

Using Trim command, trim the surface between two curves:

Trim surface

Move remaining surface from top viewport by 1 unit towards inside handle object (move both surface, and a curve that lies on the edge of that surface:

Move the surfaces

Using Line command make two lines on these tho isolated curves:

Lines

Again, make two lines, starting from corner of inner closed curve, and ending Perpendicular to the outer curve: Using Sweep2 create one surface:

Another two lines

Again, using Sweep2 make another surface:

Sweep2

Ok, now we need to fill that triangle gap with some surfaces too. We will do that with command.If you get into some problems, Split the big curve.

Triangle EdgeSrf surface

Join these surfaces:

Join surfaces

Using PolyLine command create one closed polyline:

PolyLine

Move that line so it is positioned in the middle of this surface:

Move from front and top view

Extrude this curve with ExtrudeCrv like on the image below (use BothSides=Yes options and Extrusion height is 3 units)

Extrude

Ok, now using BooleanDifference we will create a hole in our surface. But first, make sure your Normals point to outside.You will check that with command, and if the normals are towards inside, you need to flip them with command.

Dir command

BooleanDifference

Do this for the opposide side, or Mirror this. And Join these surfaces:

Join these surfaces

Using command, create a flat surface like on the image below:

SrfPt

Split the handle surface with this flat surface:

Finish

So, after applying some different Auxpacker environment maps you get your self a knife

Final

Pages: 1 2 3

used 41 commands

### 16 Responses to “Modeling Diving Knife Tutorial”

1. Brian Lake says:

AWESOME tutorial! Haven’t seen any other tutorials with this much detail!

2. Ivan says:

thanks Brian, I appreciate it ðŸ˜‰

3. Keke says:

Looks a lot like Ragde’s diving knife.

4. Ivan says:

It is. If it is “his” design.
I’m not really teaching design here, rather just modeling in Rhino.

5. Robert says:

What dimensions do you use and what version of rhino is this?

6. Ivan says:

I used centimeters, but those measures aren’t absolutely accurate, just a reference. Rhino version is v4.0 for all tutorials on this site.

is it possible to use background bitmap instead of pictureframe? for some reason pictureframe just draws a frame and there is no image. do you know why?

8. Ivan says:

sure is. you can use background bitmap. As for the image not showing in pictureframe, search the forum, there have been couple of similar questions. I’d guess it might be problem with drivers. But than again, I might be wrong.

9. Dioniso says:

Excelent tutorial. Thank you!

10. Gianluca says:

Great tutorial but i have some trouble with the first sweep 2 rail for handle. i get some strange surface result. may i send you an image by email to check what is the problem?

11. Ivan says:

go to http://www.rhino3dhelp.com/forum/index.php?board=11.0 and open a new thread with your image attached.

12. gnob says:

first of all thank you for this awesome tutorial..,, second is to cast a newbie question.. how can I view the image after I make a picture frame?? it seems no bitmap image or jpeg Appeared after the operation…pls…help… if I’m going to use background image it will appear ,but if I;m going to use picture frame it won’t appear. only a rectangular line appeared….. as this tutorial instructed is much easy to use picture frame than background image….. pls…help….Much appriciated your help and respect..

regards

13. DeigoIce says:

Yo!
Just finished the model, looks a bit diferent, but i’ve learnd a lot of tecnichs, and a lot of stuff by myself, thnx rhinoh3d!

14. Mila says:

I havnt had Rhino3D for that long and I dont know how to get the image of the diving knife into Rhino3D like in Step 1 pic 1 plea help

15. Mila says:

nvm found out how

16. shnh says:

Excelent tutorial .thank you (: