Gmax Radius Edge Tutorial

There are three methods listed in this tutorial. Depending on the situation and the object being chamfered will decide which method is the most suitable.

Method one can be applied to any edge and is faster but requires a "Smooth" modifier to achieve a smooth radius, also it can be tedious achieving equal distances for the first and second chamfer.

Method two is the most time consuming and requires a "Slice" modifier but gives a better result than the first method. It can also be very time consuming applying to edges in more than two planes or that are at an angle.

Method three is the easiest to perform however it is limited to two planes.

NOTE: Most of the editing in this tutorial is done in wireframe mode. Right click on the text in the viewport to turn on wireframe.

2. Edges

Once we have the box created and converted we then need to select the "Edge" sub-object and then select the edges of the box that we want to apply the chamfer to.

Figure 3 Chamfer type in box

Without deselecting any edges press and hold the "Control" key and then select any edges on the corners that are not selected until you have the result in figure 4

With all the required edges selected type 0.02m into the "Chamfer" box. This will chamfer the edges 0.02m and give it a more rounded look. Sometimes it can be very difficult to get the second set of radiuses right. When doing the second set remember there is always the undo button if it does not look right.

After the smooth modifier is added and configured the box should look like figure 9

Method 2.

1. Editable Box

The first thing we need to do is create a box and then convert it to editable mesh. For this tutorial the size of the box is irrelevant. Once the box is converted select the two closest top edges and chamfer them to 0.1m as shown in figure 1

Once you have the boxes edges chamfered then we need to remove the polygons from the faces of the chamfer. To do this select the "Polygon" sub-object and then holding the control key down select the two faces as shown in figure 3. Once you have the faces selected press the delete key.

2. Editable Cylinder

Now we need to create an editable cylinder. Create a cylinder with the following dimensions

Then rotate the cylinder 90 degrees in the "Y" axis convert the cylinder into an editable mesh. Select the three polygons along the top and side of the cylinder as shown in figure 4. From the "Edit Geometry" section select the "Detach" button and in the messagebox that appears make sure the two checkboxes are not checked and click on OK.

Figure 4 Polygons selected ready to be detached

Figure 5 Detach messagebox

3. Relocating and slicing

Now that we have a quarter of the cylinder we need to move into position to replace the chamfered edge of the box that we deleted. To make it easier to locate the object in the correct location go to the "Customize" menu and select "Grid and Snap Settings". In the window that opens make sure the "Endpoint" box is checked. This will allow the new object to snap into location on the box. When you have done this select the "Move" tool and place the cursor over the far lower end of the detached cylinder polygons. You will see a small blue box appear and a line will be highlighted blue also when the cursor changes to the four arrows then left click and move the object into location on to the box as shown in figure 6

Now that the curved edges are in place on the box we need to cut the polygons to the angle at the end of the box. To do this we need to apply the "Slice" modifier. After adding the slice modifier to the stack expand the modifier and select "Slice Plane". Select the "Rotate" tool and rotate the slice plane 45 degrees on the "Z" axis. Then select the move tool and move the plane towards the closest end of the box. Select the "Remove Top" radio button and the object should now have an angled end. Convert the object ot editable mesh again to remove the "Slice" modifier but retaining the angled end. Select the "Vertex" sub-object and place a window around the freshly sliced end of the object and then place the cursor over either the top or the bottom vertex until the snap box to changes to the move tool and move the vertex to the end of the box.

Figure 7 Adding a slice modifier

Figure 8 Selecting the slice plane and remove top radio button

Figure 9 Slice tool effects

Figure 10 Vertexes moved into location

4. Mirroring and relocating

Once you have the vertexes aligned we then need to create another piece for the second edge. Select the redius corner and then select the mirror tool and then mirror the object in the "X" axis. Make sure you have the "Copy" radio button checked. After you have mirrored the object then we need to rotate and move it into loacation. Select the "Rotate" tool and rotate the object 90 degrees in the "X" axis. Then select the "Move" tool and move the radius into location on the second chamfered edge.

5. Attaching and Welding

Now that we have everything in the correct location we then need to attach all the objects together. Select the box and then in the weld the vertexes together. In the "Edit Geometry" section you will see the "Attach" button select it and then click on each of the other objects. Once you have attached all the objects click on the "Attach" button again to deselect it. Now that all the objects are attached together the vertexes need to be welded together. Select the object and select "Vertex" from the sub-objects and then place a selection window over each of the visible vertices as shown in Figure 11. For each selection click on the "Weld" button in the "Edit Geometry" section and the vertexes will be welded together. Make sure that you only place the window over only one visual vertex at a time. Selecting two or more will cause them to be welded together as one.

NOTE Although there is only one vertex visible there are in fact two or more vertexes located at that point before welding.

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Method 3.

1. Spline tools

The first thing we need to do is create a line spline. The spline tools are found under the "Tool" tab "Shapes" button. For this tutorial we will be using the "Line" and the "Arc" tool.

Change the view to the "Top" view and then create the lines as shown in figure 2. I have used the grid for the size of the lines however this is not normally practicle for creating shapes for locomotives etc.Before creating the second line ensure the checkbox "Start New Shape" is not selected.

Figure 2 Created lines

Figure 3 Create New Shape checkbox

Now that the splines have been created and attached we need to set the "Interpolation" settings. This changes the number of segments required to create the arc. This also effects the poly count of the object when we extude it. For the purposes of this tutorial I have set the "Interpolation" to 1. Depending on the requirements of the object being built.

2. Extruding

After the splines have been created and attached together we then need to add an "Extrude Modifier" to the stack. Change the "Amount" in the "Parameters to the required dimension. Also make sure the "Capping" is set to "Cap Start" and "Cap End" unless you want open ends. Also ensure the "Output" is set to "Mesh" and the "Smooth" option is checked.

3. Welding vertexes

If after extruding the spline the ends were not capped and or parts of the sides did not extrude then some of the vertexes are not welded together. In the modifier stack select the "Vertex" sub-object and then place a window over each of the joins of the splines. Then under the "Geometry" section click on the "Weld" button. This welds the vertexes togther. Once you have welded all of the vertexes together, select the extrude modifier and the object should extrude again. If you welded all the vertexes together the spline should extrude correctly.

4. Convert to mesh

After you have successfully extruded the spline you can then convert it to an editable mesh. This will allow any unnecessary polygons to be deleted.

CONCLUSION

Alhough these methods both work they are by no means the only method available to create a rounded edge. The selection of a method will depend entirley on the type of object that you are working with.

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