During the last years, by looking into projects of many architectural offices, I noticed something that they had in common. Mostly in classic architectural drawings, the area that is being «cut» in a section drawing, was filled with a color. Especially in black and white drawings, it is very common to fill the section are with black color, in order to point out the difference. This technique is called «poche», and it is not something new, as it was being used in the past as well with the use of Photoshop, but just like all things, this technique has evolved as years go by. Sketchup, as we have said before, is a software, or more precisely, it is an open platform, where everyone can find and add any tool they might need. This way, we can achieve many things, which otherwise we would not be able to. Either way, Sketchup on its own, is a software with many tools and choices that can help with the final presentation.

Today I want to show you how we can achieve the «poche» technique, right through Sketchup, by using the «Section Cut Faces» tool.


In order to present to you this tool, I opened the file of a building I designed in the past, which due to its ortho-normality, it is ideal for the final result I want to have.

First of all, for this tool to operate, we have to create an active section to our building and move the section where we want our building to be cut. Then, we right-click on the section plane, and then we choose the option Add Section Cut Face.

Then a new window appears, where we have the ability to change some parameters before the final result. The first parameter is the color or the material we want to give to the interior of the section. We click on the arrow, and a drop-down list appears with colors and materials that we can choose.

By choosing, for instance, a red color, the interior of the section will appear like it is shown in the picture above.

Another option that we have, is to lock and unlock the section that we have just created, in case we want to.

If we chose to lock our section, it means that we will not be able to move that part of the section inside the building. In case we chose to leave it unlocked, then we will be able to move it wherever we want inside SketchUp.

Another parameter that we can also change, is the one of the «Auto update» of the section.

So after we have clicked the option Add Section Cut Face and the red frame appears, then we can change the position of the section, it updates by itself and transfers the red interior at the new position of the section.

So basically, what this specific tool is doing, is that it creates a surface wherever it finds that we have a section cut. This way, we can easily have, without drawing anything, the outline of the section! However, this is not the best way to produce final section drawings.

One last thing I would like to show you is another function of this tool, that is addressed to more expert users of SketchUp. You may have noticed, that if we create a section, such as the one in image 10, and then choose to render (Vray), what will appear will be the whole building, and not cut as we would expect.

But if we choose the section plane, and right-click on it, and then select the «Slice Model at Section» option, then we SketchUp will start cutting our model right where our section plane is. It basically cuts and deletes everything that exists behind that section plane at the same time, leaving only the part of our model that we see.

This means, that in many spots, it re-designs the model from the beginning. The time that it takes SketchUp to finish this process, depends of course on the complexity of our model, and how powerful our computer is. In order to understand roughly what that means, I will tell you that I have a quite powerful computer, and to finish the above cut, it took about 30-40 minutes! But, as you can see in the render, in image 12, it was worth the wait!


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