A target database plays a key role in automatic target recognition (ATR) using SAR images. To construct a target database, indirect information of the targets such as plastic models, 2-dimensional draft and pictures of them can be used to make target 3-dimensional CAD models when real targets are not accessible. Each one of the indirect information is not enough to extract the accurate shape information of targets and they should be used together to make the 3D CAD models more accurately. We used 3D graphics models that are available on the internet, 2D drafts with size information and many pictures of targets at various aspects to reverse-engineer the 3D shape of the targets in detail. This paper proposes a practical target 3D CAD modeling method using the indirect information of a target and shows the results by comparing the 3D CAD models made with indirect information with the models generated by high precision laserscanning method. In addition to comparing the 3D shape itself, RCS calculation, ISAR imaging, scattering center extraction with electromagnetics (EM) analysis code were adopted to inspect how the difference of two models affects the scattering phenomena and SAR images as a result. The result shows that once we experience the building-comparingcorrecting process several times for the generation of accurate target CAD models, decent level of target CAD models can be made using indirect information only.