Building in GMAX - finishing the other faces


We can now put the roof on using the same technique -- select a Face, press Planar Map, Edit the UVWs by moving them into position. Remember that there are ways to constrain the vertices, and we can select as many as we need to do the job.

Mapping the sides is a bit different, in that each side of the building is made up of two faces. However we can select both faces of one side, then press Planar Map, and Edit them together, as if they were one face. To select more than one face, just hold down the Ctrl key and click to add faces to the current selection.

In this case, however, we need to be a bit more careful about moving points, as we really want to retain the overall proportions, so that we don't get any slight distortion in the finished mapping. You'll know what I mean if you try moving individual points in the UVW Edit window -- parts of the texture begin to curve, and it is difficult to get a distortion-free result.

To overcome this, just use the Scale transformation. Select all the points, and scale them down to fit the and height and width of the texture for that particular side. The normal Scale tool scales in both dimensions, which is not going to exactly match the actual texture shape unless we are very lucky. We can, however, change it to just scale in the X or Y dimension. Using this tool we can fine-tune the placement.

Here I've moved the points outside the texture area so that they are more visible.

...and here is the final placement. You can also see the dropdown Scale tool choices.

What about the base of our building? There is a 'face' underneath, which we need to consider. How we deal with it, though, depends on which version we are designing for. This is where some thought needs to be given when designing for both FS2004 and FSX -- the methods have been the same up until now, but sooner or later we need to branch off to two different models.

In FS2004, it is normal practice to delete the face if it will never be seen. In FSX, however, we want to retain the 'integrity' of the shape, and removing bits is not recommended. That's because we may wish to apply a Volume Shadow to the object, and for this to work our object needs to be 'manifold', or without holes. But we can still think optimisation -- by reducing the texture coverage on the base to just a tiny part of our texture sheet, the simulator will not need to handle a large texture on an unseen face. So we select the bottom face, and choose the Scale tool to shrink the UVWs right down to tiny.


Timeout:
I said I'd give some ideas on how I design for two different versions -- FS2004 and FSX -- so I'll fit that in here.

Although there are some real differences in the completed model for the two versions, much of the work is shared, and it is easy enough to take advantage of this. The differences are mainly optimisation and texture features. So my method is to complete the model for FS2004 up to the optimisation stage. At this point the model should be 'finished', in that it includes all the geometry we want, and textured using the FS2004 gamepack. Then after saving the 'finished' model in a specific location for FS2004 models, I 'Save As' in another location for FSX.

From the time I create two separate GMAX models, each will develop separately. The FS2004 model will be optimised by removing upwanted geometry, and LODs applied (don't worry if you don't know what LODs are -- that's covered in a separate tutorial). LODs are a tricky issue here, as LODs can take time, and any shared work can save time. However LODs work best after optimisation, so it may be best to create LODs for each version.

The FSX model can have a FSX texture applied -- since we are using the same texture, the mapping will remain. Just create the FSX texture with the new features -- Volume Shadow, reflections etc -- and apply it to the model. No additional texture mapping should be necessary.

Don't forget that you will in most cases end up with two different textures in each version of the simulator -- both with the same photo detail, but the FSX version may have a reflective map included as an alpha channel. In FS2004, an alpha channel is recognised as transparency, so you can't mix and match these two textures.

Problems may arise if you decide to change the model after the work-flow is split. I also have trouble in that I normally can't wait to see my model in FSX, so I might make the split too early. However it would be possible to work the other way -- from the FSX gamepack to the FS2004 gamepack -- but this may give some problems. (FSX introduces some 'features' to the model which are not recognised by the FS2004 gamepack.)

I also said that it is possible to create FS2004 models which work well in FSX. However with the pending release of SP2 for FSX, some backward compatibility is lost. In general, though, a 'basic' texture in FS2004 -- that is, one with no extra features like transparency -- will work in FSX, provided an actual texture is applied -- not just a coloured material.

FSX OPTIMISATION UPDATE:
The method I've outlined for applying texture mapping is a simple, effective method, but it may not be the most optimal method for FSX. I may in fact be teaching some bad habits:)

In particular, resetting the planar map for each face gives a trouble-free method of mapping texture, but it may lead to a large increase in the number of vertices which need to be rendered in FSX, and since FSX works best with the minimum number of vertices, this needs to be taken into account when designing either large-vertex-count models, such as smoothly-rounded models, or models which will be place a number of times in your scenery.

Rather than cover that here, though, you should read the articles relating to vertex counts on the Torga 3000 Blog, starting with this one: Polygons don't matter.

...and here's the 'finished' model in GMAX. The actual model of this building is a bit more complex, but the idea was to show the creation of a simple object. It's now up to you to develop these techniques.

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