Hi Robert,
I will try to pick out the key points of your last few posts.
Why should I have a problem creating in TurboFloorPlan & Landscaping 3D Pro V16 using the trees provided in it's catalog ?
You shouldn't. They are not 3D trees so should not be a problem. I have used hundreds in one model with not problems at all.
Are you telling me that imported objects created in TurboCad v19 as 3ds files into TurboFloorplan & Landscaping pro v16 will be problematic? 
Not necessarily. Whether the object was created in TurboCAD or any other program makes no difference, it is still a 3DS file. There is no direct relationship between TurboCAD and TurboFloorPlan except they are both sold by IMSI Design. TC is an IMSI production, TFP is produced by Cadsoft for IMSI. You can import objects from one to the other, but only in the same way you can do that with other programs. What I am saying is that being a 3DS object created by TC does not make it any more acceptable to TFP than one created by AutoCAD, ShetchUp or any other CAD software. All potentailly produce large files and when imported to TFP can blow out memory tremendously where TFP own generations are tiny.
Not a very optimistic out look for either program, If Im limited to small house, and limited amount of fake looking trees etc.
I was hoping pro meant I can create not play 
Your are certainly not limited to a small house and fake trees. As I mentiomned before I have produced some large projects, the 62 room convention centre I mentioned earlier was by no means small and included over 2000 specially designed 3DS chairs. Look in the Gallery and you will see some large projects (eg a 9 storey office block
http://forums.turbofloorplan.com/index.php/topic,758.0.html and 12 storey apartment building
http://forums.turbofloorplan.com/index.php/topic,1604.0.html and very realistic trees as in the example below. My Convention Centre with the roof off indicates the size potential, as does Capture5. This is not mine and I do not know who actually did it now, except for the words on it, but this was done in Envisioneer. As mentioned before TFP is the 3D part of Envisioneer, so TFP could have produced exactly the same model and rendered it. The two will open, edit and render each others 3D files. Envisioneer differs only in its 2D capabilities. I simply posted it to indicate that size should not be a problem.
When I said it will not render I meant that even at the lowest quality Option. It will calculate the polygons: 3401001, and time: 375s , at 1-step Radiosity,then I will get an error message:
File parse error
file-obj_6045_0_0.ent
The number of polygons is a real worry as is the Parse Error. This indicates a corrupt element (entity) and even if the model was very small it would likely not render. The most common cause is a corrupt wall (bad wall join) or a 'corrupt' import. You will have to find the problem entity by a process of elimination. Turn off walls first and try to render again. If it works the problem is in the walls (check all the joins), If it still doesn't work, turn the walls back on and turn something else off (especially imported objects) and try again until you find the object and delete it.
P.S. The Awnings + Awning Frames- Roof metal tiles (this is the larges file do to the detail of being each tile was duplicated to the size of roof,then saved as a 3Ds single object file) and the store signs, I created with TurboCad 3D Pro V19 the trees where from 3Ds files from XFrog software
This potentiall is the biggest problem. If I am understanding this brief description correctly, it sound as though the whole roof is made of 3D 'metal tiles' and that the signs are also 3 dimentional. Normally this would be done by taking a photo of the 'tile', saving as a texture and apply to the roof and use photoboards as the signs - all of which use NO memory, as they are simply referenced from the Textures folder on your computer. Potentally this would cut the file size down dramatically and, once the curruption mentioned earlier is removed, it should render in farily short time. In fact, I would save the project with a different name, delete the '3DS roof' and try a render - maybe there is some part of that which is causing the problem. If so then you would obviously have to creat a TFP roof using a tile photo as a texture. You may get away with the signs, but if not then use photoboards. They can look very real and look 3D even if they aren't.
Allan